Adding in User Creator Helper
Add in Firebase converter methods
Removing Test User Creator
Add in Finders
Adding in Creators
Fixing typo
Addressing comments from issue #18
Merge pull request #18 from flatiron-school/find-or-create-firebase

Finding helper methods and findOrCreate
Added user extension for github dictionary conversion to user object
updated User object with optionals for all items except githubID
Added User+GithubConverter extension