Return validation errors as maps
Closes #286
Change predicates to return `nil | binary`
Update README.md

Fix typo.
Update poolboy
Try to to fix lock test race
Remove nils until we do type inference
Fix type comparison on update_all

Closes #310.
Mix tasks now use port if specified in ecto URL
Add and document Ecto.Query.API.array/2.
Fix code quote in docs
Add missing docs for one, one! and get!
Remove duplicated join code
bump ecto version number in readme
Explicitly stand out that the SQL is not generated
Document invariant for Ecto.Repo.log/2
Updating poolboy to 1.4.1 re #320
Adding logger to generator
mend
Fixing require logger, and remove space
removing extra whitespace