Remove duplicated associations
Remove Channel#channels_subscribers association

It causes an error in the test suite but is not being used anywhere
(just a join table).
Merge pull request #417 from neighborly/im-active-record-warnings

Get rid of ActiveRecord's warnings after upgrade to Rails 4.1.3
Add user.email to searchable scope of projects

As [requested](https://github.com/neighborly/neighborly-api/issues/12#issuecomment-47950713)
by @snconnolly.