diff --git a/.github/workflows/blank.yml b/.github/workflows/blank.yml
index 8a57aeb..3617f56 100644
--- a/.github/workflows/blank.yml
+++ b/.github/workflows/blank.yml
@@ -12,15 +12,131 @@ on:
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
+  github-context:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Dump github context
+        run:   echo "$GITHUB_CONTEXT"
+        shell: bash
+        env:
+          GITHUB_CONTEXT: ${{ toJson(github) }}
+
+  matrix-testing:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ "ubuntu-latest", "macos-latest"]
+        python-version: [ "3.7", "3.8", "3.9"]
+        wo_gurobi: ["", "without gurobi"]
+        include:
+          - os: "ubuntu-latest"
+            minizinc_path: $(pwd)/bin
+          - os: "macos-latest"
+            minizinc_path: $(pwd)/bin/MiniZincIDE.app/Contents/Resources
+          - coverage: false
+          - os: "ubuntu-latest"
+            python-version: "3.9"
+            wo_gurobi: ""
+            coverage: true
+        exclude:
+          - os: "macos-latest"
+            wo_gurobi: "without gurobi"
+          - os: "ubuntu-latest"
+            wo_gurobi: "without gurobi"
+            python-version: 3.7
+          - os: "ubuntu-latest"
+            wo_gurobi: "without gurobi"
+            python-version: 3.8
+
+    steps:
+      - name: on teste la matrice
+        run: |
+          echo ${{ matrix.wo_gurobi }}
+          echo ${{ matrix.minizinc_path }}
+          if [ "${{ matrix.wo_gurobi }}" = "without gurobi" ]; then
+              echo pip install gurobipy
+          fi
+          echo ${{ matrix.coverage }}
+          if ${{ matrix.coverage }}; then
+            echo "Add a coverage report"
+          fi
+      - name: on fait pytest normal
+        if: ${{ !matrix.coverage }}
+        run: echo "pytest"
+      - name: on fait pytest avec coverage
+        if: ${{ matrix.coverage }}
+        run: echo "pytest --cov"
+
   # This workflow contains a single job called "build"
   build:
     # The type of runner that the job will run on
     runs-on: ubuntu-latest
-
+    env:
+          python_version: "3.7"
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v2
+      - name: Setup python
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ env.python_version }}
+      - name: Test python
+        run: python --version
+      - name: Checkout all branches
+        uses: actions/checkout@v2
+        with:
+          submodules: true
+          fetch-depth: 0  # fetch all branches
+
+      - name: build master doc (fake it by appending a word)
+        run: |
+          git show origin/gh-pages:yo.md > doc/yo.md
+          echo "yo" >> doc/yo.md
+
+      - name: Deploy documentation in root folder on GH pages 🚀
+        uses: JamesIves/github-pages-deploy-action@4.1.5
+        with:
+          branch: gh-pages # The branch the action should deploy to.
+          folder: doc # The folder the action should deploy.
+          target-folder: / # The folder the action should deploy to.
+          commit-message: publish documentation for master
+          clean-exclude: |
+            "version/*"
+
+      - name: Checkout all branches
+        uses: actions/checkout@v2
+        with:
+          submodules: true
+          fetch-depth: 0  # fetch all branches
+
+      - name: Squash last master doc commits on gh_pages
+        run: |
+          git checkout gh-pages
+          # check if two last commits are for same doc
+          last_commit_title=$(git log HEAD -1 --format=%s)
+          second_to_last_commit_title=$(git log HEAD~1 -1 --format=%s)
+          echo $last_commit_title 
+          echo $second_to_last_commit_title
+          if [[ $last_commit_title == $second_to_last_commit_title ]]; then
+            echo "Merge two last commits"
+            git reset --soft HEAD~
+            git config user.name "Actions"
+            git config user.email "actions@github.com"
+            git commit --amend --no-edit
+            git push -f origin gh-pages
+          fi
+
+
+      - name: Tests
+        run: |
+          echo $GITHUB_REF
+          echo ${{ github.ref }}
+          echo ${{ github.ref_name }}
+          echo ${{ github.head_ref }}
+          echo ${{ github.base_ref }}
+          echo ${{ github.repository }}
+          echo $GITHUB_REPOSITORY
 
       - name: Set env variables for github+binder links in doc
         run: |
@@ -53,6 +169,8 @@ jobs:
           echo ${AUTODOC_NOTEBOOKS_REPO_URL}
           echo ${AUTODOC_NOTEBOOKS_BRANCH}
 
+          echo nb_branch: ${{ env.AUTODOC_NOTEBOOKS_BRANCH }}
+
       # Runs a single command using the runners shell
       - name: Run a one-line script
         run: echo  ${{ github.ref }}
@@ -65,4 +183,3 @@ jobs:
       - name: deploy
         if: ${{ github.ref == 'refs/heads/main' }}
         run: echo deploy
-
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b7a9b44..7ea876b 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -10,39 +10,44 @@ on:
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
-  # This workflow contains a single job called "build"
-  build:
-    # The type of runner that the job will run on
+  create-binder-env:
     runs-on: ubuntu-latest
-
-    # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
-      # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
+      - name: Get scikit-decide release version and define new binder env tag
+        run: |
+          TAG_NAME=${GITHUB_REF/refs\/tags\//}  # stripping "refs/tags/"
+          SKDECIDE_VERSION=${TAG_NAME/v/}  # stripping "v"
+          BINDER_TAG=binder_${TAG_NAME}
+          echo "BINDER_TAG=${BINDER_TAG}" >> $GITHUB_ENV
+          echo "SKDECIDE_VERSION=${SKDECIDE_VERSION}" >> $GITHUB_ENV
+          echo "DOCS_VERSION_PATH=/version/$SKDECIDE_VERSION/" >> $GITHUB_ENV
+
+      # Checks-out current branch
       - uses: actions/checkout@v2
 
+      - name: Deploy 🚀
+        uses: JamesIves/github-pages-deploy-action@4.1.5
+        with:
+          branch: gh-pages # The branch the action should deploy to.
+          folder: doc # The folder the action should deploy.
+          target-folder: ${{ env.DOCS_VERSION_PATH }} # The folder the action should deploy to.
+          commit-message: publish documentation for release ${{ env.SKDECIDE_VERSION }}
+          clean: false # Releasing a new version is about creating a new directory, so we don't want to clean up the root.
+
+  build-docs:
+    runs-on: ubuntu-latest
+    env:
+      DOCS_VERSION_PATH: /
+
+    steps:
       - name: Set env variables for github+binder links in doc
         run: |
-          # binder environment repo and branch
-          AUTODOC_BINDER_ENV_GH_REPO_NAME="airbus/scikit-decide"
-          AUTODOC_BINDER_ENV_GH_BRANCH="binder"
-          # notebooks source repo and branch depending if it is a commit push or a PR
-          if [[ $GITHUB_REF == refs/pull* ]];
-          then
-              AUTODOC_NOTEBOOKS_REPO_URL="${GITHUB_SERVER_URL}/${{ github.event.pull_request.head.repo.full_name }}"
-              AUTODOC_NOTEBOOKS_BRANCH=${GITHUB_HEAD_REF}
-          elif [[ $GITHUB_REF == refs/heads* ]];
-          then
-              AUTODOC_NOTEBOOKS_REPO_URL=${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}
-              AUTODOC_NOTEBOOKS_BRANCH=${GITHUB_REF/refs\/heads\//}
-          fi
-          # export in GITHUB_ENV for next steps
-          echo "AUTODOC_BINDER_ENV_GH_REPO_NAME=${AUTODOC_BINDER_ENV_GH_REPO_NAME}" >> $GITHUB_ENV
-          echo "AUTODOC_BINDER_ENV_GH_BRANCH=${AUTODOC_BINDER_ENV_GH_BRANCH}" >> $GITHUB_ENV
-          echo "AUTODOC_NOTEBOOKS_REPO_URL=${AUTODOC_NOTEBOOKS_REPO_URL}" >> $GITHUB_ENV
-          echo "AUTODOC_NOTEBOOKS_BRANCH=${AUTODOC_NOTEBOOKS_BRANCH}" >> $GITHUB_ENV
-          # check computed variables
-          echo "Binder env: ${AUTODOC_BINDER_ENV_GH_REPO_NAME}/${AUTODOC_BINDER_ENV_GH_BRANCH}"
-          echo "Notebooks source: ${AUTODOC_NOTEBOOKS_REPO_URL}/tree/${AUTODOC_NOTEBOOKS_BRANCH}"
+          TAG_NAME=${GITHUB_REF/refs\/tags\//}  # stripping "refs/tags/"
+          BINDER_TAG=binder_${TAG_NAME}
+          echo "AUTODOC_BINDER_ENV_GH_REPO_NAME=airbus/scikit-decide" >> $GITHUB_ENV
+          echo "AUTODOC_BINDER_ENV_GH_BRANCH=${BINDER_TAG}" >> $GITHUB_ENV
+          echo "AUTODOC_NOTEBOOKS_REPO_URL=${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}" >> $GITHUB_ENV
+          echo "AUTODOC_NOTEBOOKS_BRANCH=${TAG_NAME}" >> $GITHUB_ENV
 
       - name: read binder env
         run: |
@@ -50,17 +55,3 @@ jobs:
           echo ${AUTODOC_BINDER_ENV_GH_BRANCH}
           echo ${AUTODOC_NOTEBOOKS_REPO_URL}
           echo ${AUTODOC_NOTEBOOKS_BRANCH}
-
-      # Runs a single command using the runners shell
-      - name: Run a one-line script
-        run: echo  ${{ github.ref }}
-
-      # Runs a set of commands using the runners shell
-      - name: Run a multi-line script
-        run: |
-          echo Add other actions to build,
-          echo test, and deploy your project.
-      - name: deploy
-        if: ${{ github.ref == 'refs/heads/main' }}
-        run: echo deploy
-
diff --git a/.github/workflows/workflow2.yml b/.github/workflows/workflow2.yml
deleted file mode 100644
index e8a1cf6..0000000
--- a/.github/workflows/workflow2.yml
+++ /dev/null
@@ -1,26 +0,0 @@
-# This is a basic workflow to help you get started with Actions
-
-name: workflow 2
-
-# Controls when the workflow will run
-on:
-  workflow_run:
-    workflows:
-      - CI 🔨
-    types:
-      - completed
-  # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
-
-# A workflow run is made up of one or more jobs that can run sequentially or in parallel
-jobs:
-  # This workflow contains a single job called "build"
-  build:
-    # The type of runner that the job will run on
-    runs-on: ubuntu-latest
-
-    # Steps represent a sequence of tasks that will be executed as part of the job
-    steps:
-      # Runs a single command using the runners shell
-      - name: Run a one-line script
-        run: echo "workflow 2 working!"
diff --git a/.github/workflows/workflow3.yml b/.github/workflows/workflow3.yml
deleted file mode 100644
index 10b2973..0000000
--- a/.github/workflows/workflow3.yml
+++ /dev/null
@@ -1,32 +0,0 @@
-# This is a basic workflow to help you get started with Actions
-
-name: workflow 3
-
-# Controls when the workflow will run
-on:
-  workflow_run:
-    workflows:
-      - CI 🔨
-    types:
-      - completed
-
-      # Allows you to run this workflow manually from the Actions tab
-  workflow_dispatch:
-
-# A workflow run is made up of one or more jobs that can run sequentially or in parallel
-jobs:
-  # This workflow contains a single job called "build"
-  build:
-    if: ${{ github.event.workflow_run.conclusion == 'success' }}
-    # The type of runner that the job will run on
-    runs-on: ubuntu-latest
-
-    # Steps represent a sequence of tasks that will be executed as part of the job
-    steps:
-      - uses: actions/checkout@v2
-      # Runs a single command using the runners shell
-      - name: Run a one-line script
-        run: echo "workflow 3 working on other branch!"
-      - name: only on main
-        run: echo "only on main branch"
-        if: ${{ github.event.workflow_run.head_branch == 'main' }}
\ No newline at end of file
diff --git a/doc/a b/doc/a
new file mode 100644
index 0000000..e69de29
diff --git a/doc/anpother b/doc/anpother
new file mode 100644
index 0000000..e69de29
diff --git a/doc/b b/doc/b
new file mode 100644
index 0000000..e69de29
diff --git a/doc/c b/doc/c
new file mode 100644
index 0000000..e69de29
diff --git a/doc/masterreadme.md b/doc/masterreadme.md
new file mode 100644
index 0000000..e69de29
diff --git a/doc/newone b/doc/newone
new file mode 100644
index 0000000..e69de29
diff --git a/doc/yo.md b/doc/yo.md
new file mode 100644
index 0000000..a5e03e6
--- /dev/null
+++ b/doc/yo.md
@@ -0,0 +1,3 @@
+\nyo
+\nyo
+yo
diff --git a/new_feature b/new_feature
new file mode 100644
index 0000000..e69de29