Add method to keep track of which project the user came from
Add a method to complete all introduction steps
Pass the project param to the sign up path
Add completed before sign up  to introduction steps
Set the completed_before_sign_up boolean on intro step progresses
Fix migration to be on introduction steps
Merge pull request #1381 from teamleada/mark-sign-up-project

Sign up redirects to the project you were just on
Center image on the home page. Fix #1382
Merge branch 'master' of github.com:teamleada/teamleada.com
Remove about header
Clean up footer and remove old links
Add projects and tracks link to footer