Add Welcome message

[evijit]

Show a welcome message when a new user texts the bot for the first time.

[rghv96]

There's an option of messenger greetings in the settings of the page of bot.

[evijit]

There's also an option in the API.

[Amskee]

How can we edit yout API.ai agent without having access to it ?

[evijit]

@Amskee access is given to the agent. It is public. Check sheldon.zip in readme..