Merge pull request #8 from decatan/master

Updated gemfile for new bootstrap gems
Merge pull request #9 from decatan/master

Got the page to work again
Merge pull request #10 from decatan/master

Added user signin-out backend
Merge pull request #11 from decatan/master

Made headers to react to sign in and out
Merge pull request #12 from decatan/master

Added gravatar_for method