Add PreCommit::PreventDebugger
Remove logger.debug validation on prevent_debugger

As @leafac and @carloslopes told, I am removing the logger.debug from black
list.

"I don't agree with the decition of not allowing logger.debug. It may be
useful to leave some debug level logs in production code. Then, when
some nasty bug arrises, the log level in production processes can be
changed for a while to track it down." @leafac

"Yes, logger.debug is totally acceptable and useful in production."
@carloslopes
Merge pull request #8 from stupied4ever/prevent-debuggers

Add PreCommit::PreventDebugger
Update Readme
Add travis yml
Add coveralls
Add all the bagdes
Fix double leaked into another example
Merge pull request #12 from stupied4ever/all-the-badges

All the badges
Create installation class
Add whitespace validation
Rename `Whitespace` to `TrailingWhitespace`
Handle Errno::EEXIST on hook installation
Rename Installer#hook_installed? to installed?
Add force option on CLI
Fix typo
Merge pull request #14 from stupied4ever/fix-installation

Fix installation
Merge pull request #11 from rranelli/whitespace-validation

Add whitespace validation.
Release version 0.2.0
Fix undefined method `git_repository'