testing with shoulda matchers
video and category model associations and validations tested
added uniqueness validation to category model and create appropriate test
removed slugging per suggestions
cleaned up validations
added pry and pry-nav to gemfile
removed duplicate gems
Merge pull request #2 from davefedele/mod1

testing with shoulda matchers
removed slugging
pry and pry-nav gems to development and test block
cleaned up validations