Travis CI
Remove debugger gem
Merge pull request #1871 from kubasub/master

RSpec test
Update travis.yml
Added debugger gem to development group
Merge pull request #1873 from david-yz-liu/travis-ci

Add Travis CI
Haskell highlighting
Fix up the brush
Merge pull request #1874 from david-yz-liu/haskell-syntax

Add Haskell syntax highlighting