Profile tagging

This pull requests adds functionality for tagging a user's profile with 'skills and expertise'.

To disable this feature by hiding the 'Skills and expertise' field from the edit profile page:
`config.disable_profile_tagging`

In the course of this work I discovered that the tests weren't running on travis so a few of these commits are related to fiddling with the rubocop, rspec and jshint set up.