create contributor model class
create Contributor controller and routes
create view to show all contributors
add form to create new contributors. add twitter bootstrap css
add save functionality
add some styles
add  styles
add persistence using ebean
allow to delete contributors
contribution main classes and views
add contribution crud
add contribution type field
allow adding several contributors to a contribution - without persistence
show selected contributors
allow to delete contributions
many to many relationship
add contribution type CRUD
add relationships between contribution and contributionType
add roles to contributors
add roles to contributors