Update README.md

Fix typo.
Merge pull request #307 from Chipairon/patch-1

Update README.md
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
Merge pull request #312 from stevedomin/steve-mix-use-port

Mix tasks now use port if specified in ecto URL
Add and document Ecto.Query.API.array/2.
Merge pull request #315 from alanpeabody/add-and-doc-array/2

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
Merge pull request #317 from lancehalvorsen/bump-package-versions-in-readme

Bump Versions for Ecto and Postgrex in README.md
Explicitly stand out that the SQL is not generated
Merge pull request #318 from trenpixster/patch-1

Explicitly stand out that the SQL is not generated
Document invariant for Ecto.Repo.log/2
Merge pull request #319 from Havvy/master

Document invariant for Ecto.Repo.log/2
Updating poolboy to 1.4.1 re #320