Refactor fetchDepartutureEstimates method to simplify worker logic
Refactor twilio module to make it require only original station and direction
Make destination field no longer required.  Update the existing specs to reflect this schema change
Add final callback to ensure that the process terminates itself when all jobs completed
Merge pull request #10 from ryojiosawa/promise

Refactor fetchDepartutureEstimates method to simplify worker logic