Setup greenkeeper and grenkeeper-keeper

[tsirlucas]

[tsirlucas]

blocked by #6

[tsirlucas]

greenkeeper is working, however, it only works for free in open source projects. grenkeeper-keeper wil be added once tests are with 100% coverage

[tsirlucas]

greenkeeper working 100% blocked by #6 once a good test coverage is necessary to enable greenkeeper-keeper