Add -fwarn-tabs to ghc-options.

Closes: #35
Merge pull request #36 from erikd/postgres

Add -fwarn-tabs to ghc-options.
Move keter postgres configuration under plugins.

This fixes snoyberg/keter#46 for v1.0 Keter config syntax.
Merge pull request #37 from creichert/postgres

Move keter postgres configuration under plugins.
Merge branch 'postgres' into simple
Add ViewPatterns extension to Cabal file

(Yesod 1.4 adds a dependency on this extension for routes like `/articles/#Int ArticleR GET`)
Merge pull request #38 from MaxGabriel/patch-1

Add ViewPatterns extension to Cabal file
Merge branch 'postgres' into simple