Add groupBy utility function for use in TimeLog.

Dependencies

• [2] NVOCQVAS Initial failing tests.

Change contents

• edit in src/Ananke/TimeLog.hs at line 18
  [2.1194]

  [2.1194]
  + import Control.Arrow
• edit in src/Ananke/TimeLog.hs at line 55
  [2.2419]
  +

  + groupBy f = fromListWith (++) . fmap (f &&& pure)