Add docs to setup corobo

This illustrates the steps involved in setting up corobo in text mode and with gitter-backend.

docs/setup.rst

@@ -0,0 +1,90 @@
+Setting Up Corobo
+=================
+
+The following documentation illustrates the process to install Corobo and interface it with the gitter API.
+
+Installation
+------------
+
+*  To install corobo, first you need to setup a virtual environment(it is not mandatory but highly recommended). This can be done as follows:
+   ::
+     pip3 install virtualenv
+     virtualenv venv -p python
+     cd venv
+     source bin/activate ---->  For Linux
+     \Scripts\activate   ---->  For Windows
+*  Next, you can clone the corobo package via git and install the requirements(dependent packages).
+   ::
+     git clone https://github.com/coala/corobo.git
+     pip install -r requirements.txt
+
+Configuration of Environment variables(In text mode)
+--------------------------------------------------
+
+*  The following environment variables are required to setup corobo in text mode:
+   ::
+     export BOT_PREFIX="any_name"
+     export BACKEND="Text"
+     export BOT_USERNAME="@any_other_name"
+   (**Note:** The BOT_USERNAME always starts with a @ for a person and # for a room)
+
+Testing Corobo
+---------------------------
+
+*  To run the bot use:
+   ::
+     errbot
+*  You can test the bot using the following commands:
+   ::
+     bot_prefix help    ----> Lists the set of commands available with the bot
+     bot_prefix history ----> Lists the command history
+     
+     
+Setting up Corobo with gitter backend
+=====================================
+
+#. Clone the err-backend-gitter repository in your "corobo" folder.
+   ::
+     git clone https://github.com/errbotio/err-backend-gitter.git
+     
+#. Configure the environment variables(for gitter-backend).
+   ::
+     export BACKEND="Gitter"
+     export BOT_EXTRA_BACKEND_DIR="/path_to/err-backend-gitter"
+#. To make the bot interact with the gitter API you will need a github account(this account can be used to login to gitter) to generate the gitter access token.
+   **Remember it is recommended to use a separate account(other than the admin account) for the bot.** 
+   Once the account is setup, run the following script.
+   ::
+     ./oauth.py
+   This will guide you with the gitter token generation process.
+#. Now you can assign the above generated token to the BOT_TOKEN environment variable.
+   ::
+     export BOT_TOKEN="your_gitter_token"
+#. Also to configure the bot with access to your github and gitlab repositories, you will need personal access tokens.
+   The following links may guide you through this:
+     https://docs.github.com/en/github/authenticating-to-github/creating-a-personal-access-token
+     https://docs.gitlab.com/ee/user/profile/personal_access_tokens.html
+#. You can also create github organisations and gitlab groups to manage your repositories.
+   Under a organisation you can make teams to organize the workforce.
+#. After completing the above steps, it is time to setup the remaining environment variables with the above gathered information.
+   ::
+     export GH_TOKEN="your_github_token"
+     export GL_TOKEN="your_gitlab_token"
+     export GH_ORG_NAME="your_github_organisation_name"
+     export GL_ORG_NAME="your_gitlab_organisation_name"
+     export ROOMS="rooms_to_join"
+     export BOT_ADMINS="your_gitter_username"
+   (**Note:** The admin user account should be different than the bot account.)
+#. Hurrah!!! the bot is now ready to be deployed. To run the corobo instance use:
+   ::
+     errbot
+
+Your corobo instance should now be running. You can chat with the bot by logging in through the admin gitter account and 
+searching its username in the contacts section. You can send it commands via chat.
+::
+  bot_prefix help
+  bot_prefix history
+  
+**Note:** Every time you run a new instance of the bot, it is required to set the environment variables(steps 2 and 7).
+
+To know more about the list of available commands and other features of corobo checkout the other `docs <https://github.com/coala/corobo/tree/master/docs>`_.