[JRO] Create and display a simple topic

The first topic feature is now passing - it tests that a logged in user
can visit a messageboard (with the appropriate permissions), create a
new topic with a title and content body, see that the topic is
listed and then correctly displayed with its initial post.
[JRO] Users are able to create topics

Cool.

* Remove all observers from the app.
* Add Topic#decorate and Topic.decorate will run an object, or AR query through the topic decorator. Ok Cool.
* Clean up the views