Updates rails from 4.1.5 to 4.1.6

- Updates rails from 4.1.5 to 4.1.6
- Adds additional assets to `config.assets.precompile` per runtime
error warnings from the Rails asset pipeline.
Merge pull request #657 from codeforamerica/update-rails

Updates rails from 4.1.5 to 4.1.6