Merge tag 'v1.1.1'

1.1.1
Update contribution guidelines

Replace commit signing process with https://cla.strongloop.com/
Make sure callback happens if a model is not attached to the data source
Merge pull request #5 from strongloop/feature/fix-automigrate-callback

Make sure callback happens if a model is not attached to the data source
Bump version
Merge branch 'release/1.2.0' into production