[WIP] Rake task for pulling in Brigade meetup info and upcoming events

Just wanted to send a request for this before I forget, it's been sitting in an idle branch of mine for ~2 weeks.

It's very much a work-in-progress and **not ready to be merged with master**.

I was hoping that we might be able to pull in basic meetup descriptions/info/events for each brigade provided they have a supplied `meetup_url` in the table. That way the `Brigades#show` page isn't so blank if the Brigade hasn't deployed an app yet. It would also be great to have the next event shown for each Brigade.

I'm open to any thoughts/changes on this.

Still to do:

- [ ] Integrate `meetup_json_data` into controllers and views
- [ ] Get rid of API key
- [ ] Clean the retrieved json descriptions; currently it returns raw html, \n newlines everywhere, etc.
- [ ] Have the heroku scheduler automagically run the rake tasks daily
- [ ] Refactor rake tasks (currently they overwrite each other in `meetup_json_data`)