WIP: Search for Community using elasticsearch

First cuts for search feature for Community
There's a thread that starts with "Beginning iOS Workshop at Hacker School". We noticed that typing "ios" into the search box showed it as a suggestion, but "ios workshop" didn't. We now think it's because of the above. Instead of just including the whole title and the title split on whitespace, we additionally need to include everything after the first word, and then after the second word, etc. Example:

```ruby
["Beginning", "iOS", "Workshop", "at", "Hacker", "School"]
["iOS", "Workshop", "at", "Hacker", "School"]
["Workshop", "at", "Hacker", "School"]
#etc.
```