Added requirement in class docblock

fix for https://github.com/netmanagers/puppet-nginx/issues/48
Correcting syntax error in README.md, replacing ; by ,
Update travis matrix
Add updated gemfile
Trying to make travis happy... again
Update travis matrix
Merge pull request #62 from jhooyberghs/master

Correcting syntax error in README.md, replacing ; by ,
Merge pull request #58 from yanickj/master

Added requirement in class docblock