Profile tagging

This pull requests adds functionality for tagging a user's profile with 'skills and expertise'.

To disable this feature (basically, hiding the skills/expertise form 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.