diff --git a/instark/core/data/sql/migrations/003_create_selections_table.py b/instark/core/data/sql/migrations/003_create_selections_table.py
new file mode 100755
index 0000000..d998a0a
--- /dev/null
+++ b/instark/core/data/sql/migrations/003_create_selections_table.py
@@ -0,0 +1,28 @@
+class Migration:  # pragma: no cover
+    version = '003'
+
+    def __init__(self, context):
+        self.context = context
+        self.connection = context['connection']
+        self.schema = context['schema']
+        self.owner = "instark"
+        self._tables = ["channels", "devices", "messages",
+                        "subscriptions"]
+
+    def _create_table(self, table):
+        return (
+            f"CREATE TABLE IF NOT EXISTS {self.schema}.{table} (data JSONB);"
+            f"ALTER TABLE {self.schema}.{table} OWNER TO {self.owner};"
+            f"CREATE UNIQUE INDEX IF NOT EXISTS {table}_id_key ON "
+            f"{self.schema}.{table} ((data->>'id'));"
+        )
+
+    def schema_up(self):
+        statement = ""
+        for table in self._tables:
+            statement += self._create_table(table)
+
+        self.connection.execute(statement)
+
+    def schema_down(self):
+        """Not implemented."""
diff --git a/instark/presenters/rest/rest.py b/instark/presenters/rest/rest.py
index 2c88c70..159eee3 100644
--- a/instark/presenters/rest/rest.py
+++ b/instark/presenters/rest/rest.py
@@ -1,4 +1,3 @@
-import aiohttp_cors
 import aiohttp_jinja2
 from typing import Any
 from pathlib import Path
@@ -29,17 +28,10 @@ def _setup(self) -> None:
         aiohttp_jinja2.setup(self, loader=FileSystemLoader(templates))
 
         self.cleanup_ctx.append(self._http_client)
-        cors = aiohttp_cors.setup(self, defaults={
-            "*": aiohttp_cors.ResourceOptions(
-                allow_credentials=True, expose_headers="*",
-                allow_headers="*")})
 
         # API endpoints creation
         self._create_api()
 
-        for route in list(self.router.routes()):
-            cors.add(route)
-
     @staticmethod
     async def _http_client(app: web.Application):
         session = ClientSession()
diff --git a/requirements.txt b/requirements.txt
index 7fc6fba..e187052 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,34 +1,20 @@
 aiocontextvars==0.2.2
 aiohttp==3.6.2
-aiohttp-cors==0.7.0
 aiohttp-jinja2==1.2.0
-alabaster==0.7.12
-aniso8601==7.0.0
-ansible==2.8.4
+aiomcache==0.6.0
 apispec==3.3.2
-appdirs==1.4.3
-argh==0.26.2
-asn1crypto==0.24.0
-astroid==2.2.5
 async-timeout==3.0.1
-asyncmock==0.4.1
 asyncpg==0.21.0
-atomicwrites==1.3.0
+atomicwrites==1.4.0
 attrs==20.1.0
-autopep8==1.4.4
-Babel==2.7.0
-bcrypt==3.1.7
+autopep8==1.5.4
+bump2version==1.0.0
 CacheControl==0.12.6
 cachetools==4.1.1
 certifi==2020.6.20
 cffi==1.14.2
 chardet==3.0.4
-colorama==0.4.3
-contextlib2==0.6.0
 coverage==5.2.1
-cryptography==2.7
-distlib==0.3.0
-distro==1.4.0
 filtrark==0.9.3
 firebase-admin==4.3.0
 google-api-core==1.22.1
@@ -42,53 +28,45 @@ google-crc32c==1.0.0
 google-resumable-media==1.0.0
 googleapis-common-protos==1.52.0
 grpcio==1.31.0
-html5lib==1.0.1
 httplib2==0.18.1
 idna==2.10
 iniconfig==1.0.1
 injectark==0.4.1
-ipaddr==2.2.0
 Jinja2==2.11.2
-lazy-object-proxy==1.4.2
-lockfile==0.12.2
 MarkupSafe==1.1.1
 marshmallow==3.7.1
 migrark==0.6.0
-mock==3.0.5
-modelark==0.2.3
+modelark==0.2.7
+
 more-itertools==8.5.0
 msgpack==1.0.0
 multidict==4.7.6
 packaging==20.4
-pep517==0.8.2
+pgdb==0.0.8
 pluggy==0.13.1
-progress==1.5
 protobuf==3.13.0
 py==1.9.0
 pyasn1==0.4.8
 pyasn1-modules==0.2.8
-pycodestyle==2.5.0
+pycodestyle==2.6.0
 pycparser==2.20
 PyGreSQL==5.2
 pyparsing==2.4.7
 pytest==6.0.1
 pytest-aiohttp==0.3.0
 pytest-asyncio==0.14.0
+pytest-clarity==0.3.0a0
 pytest-cov==2.10.1
-pytoml==0.1.21
 pytz==2020.1
-PyYAML==5.1.2
-rapidjson==1.0.0
 requests==2.24.0
-retrying==1.3.3
 rsa==4.6
 six==1.15.0
 tenark==0.8.3
+termcolor==1.1.0
 toml==0.10.1
-typed-ast==1.4.0
 uritemplate==3.0.1
 urllib3==1.25.10
 uvloop==0.14.0
-webencodings==0.5.1
-wrapt==1.11.2
+wcwidth==0.2.5
+widark==0.3.3
 yarl==1.5.1