[ADD] discuss: Integrating Twitter Feed with Channels

added doc for creating a twitter app and getting API keys

discuss/integrations/mail_twitter.rst

@@ -1,3 +1,41 @@
 ======================================
 Integrating Twitter Feed with Channels
 ======================================
+
+.. image:: media/twitter_user-image.png
+    :align: center
+
+A user can follow specific hashtags on twitter and see the tweets within the 
+channels of his/her choice. The tweets are retrieved periodically from Twitter.
+An authenticated user can retweet the messages.
+
+Setting up the App on Twitter's side
+====================================
+
+Twitter uses an "App" on its side which is opens a gate to which Odoo asks for
+tweets, and through which a user can retweet.
+To set up this app, go to http://apps.twitter.com/app/new and put in the values:
+
+- Name: this is the name of the application on Twitter
+
+- Website: this is the external url of your Odoo database, with "/web" added.
+  For example, if your Odoo instance is hosted at "http://www.example.com", you
+  should put "http://www.example.com/web" in this field.
+
+- Callback URL: this is the address on which Twitter will respond. Following the
+  previous example you should write "http://www.example.com/web/twitter/callback".
+
+Do not forget to accept the terms **Developer agreement** of use and click on
+**Create your Twitter application** at the bottom of the page.
+
+
+Getting the API key and secret
+==============================
+
+When on the App dashboard, switch to the **Keys and Access Tokens** tab.
+
+.. image:: media/api_key.png
+    :align: center
+
+And copy those values in Odoo in :menuselection:`Settings--> General Settings--> Twitter discuss integration`
+and click on **Save** to save the settings.