Added basic admin brew functionality - add new brew, list brews.

Updated UI on the admin page as well.

Lessons learned:
1. When adding a new module to the app, make sure it's included in the karma.conf.js file so tests do not unexpectedly fail.
2. Use of the auth module in routes affects tests directly - still need to test various brew controller methods once we find out how to simulate making a POST request as an 'admin' user, etc.