Join public rooms from search
There are a few items that provide some background to this: https://trello.com/c/71gPhMQl https://trello.com/c/QaYTtded https://twitter.com/Turbo3AA9F/status/438957688685608960
- If a user types owner/repo in the search box and there is a public room that matches, we should show the room in the search results.
- Partial matches? E.g. just "gitter" for "gitterHQ/gitter"