Allow format validators to be used on update
Add cache_dir to allowed paths
Update README.md

Fix Non-ActiveRecord object example in README.md.
Merge pull request #150 from samuelreh/master

Update README.md
Merge pull request #133 from greysteil/better-validations

Allow format validators to be used on update
replace be_true/be_false -> be true/be false
Remove deprecation warnings
Merge pull request #152 from hanachin/rspec3

Fixed specs for rspec 3
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Remove deprecation warnings
  replace be_true/be_false -> be true/be false
  Update README.md
  Add cache_dir to allowed paths
  Allow format validators to be used on update