Update factory_girl_rails
Add database_cleaner gem
Add DatabaseCleaner to run before each test
Add FactoryGirl.lint to run before the test suite

FactoryGirl.lint will check if every factory is valid before running the
test suite
Fix AdminUser and Answer factories
Merge branch 'refactor-factories' of https://github.com/edgurgel/askaway into edgurgel-refactor-factories

Conflicts:
	Gemfile.lock
	spec/factories/answers.rb