Add Contributor's Guide
Fix wrong relative path for lib/rmagick/version
Merge pull request #139 from marwan-tanager/master

Fix wrong relative path for lib/rmagick/version
Merge pull request #136 from vassilevsky/contributors-guide

Add Contributor's Guide
Fix version.rb require path

During compilation, extconf.rb is located in
tmp/x86_64-linux/RMagick2/$RUBY_VERSION
fix path for build
Merge pull request #142 from mockdeep/path_fix

Fix version require path
Make Travis notify Gitter chat room 'gemhome'
Reroute Travis notifications to rmagick repo chat
Add Gitter badge to README
Put all badges in one line

Unfortunately, there doesn't seem to be a way to do this while keeping
the source code in separate lines :(
adding rubocop