Make travis test some different ruby versions.
Add some more rubies to travis.
Add whitelist_branches method to ConfigFile.
Add support for whitelisted branches to PullRequestsData.
Change whitelist to use Set instead of array.
safe to remove default spec test now
simplify whitelist branches config file logic
fix spec test
make spec tests in line with proposed changes
remove empty line
simplify pull request selection code
bring spec tests in line with changes
remove empty line
small change in config comments
Merge pull request #3 from vaneyckt/vhladama-whitelist-review

Vhladama whitelist review
Merge pull request #29 from vhladama/whitelist

New feature: Allow specifying a list of base branches to white list, and ignore pull requests targeting other branches.