Import contribution policy from catarse
Refactor contribution policy
Remove payment_service_fee_paid_by_user from permited params in contribution policy
Migrate user contributions controller to pundit
Migrate project contributions to pundit
Remove cancan from users/contributions controller
Remove update action from projects/contributions controller
Remove unuset methods from contribution model
Refactor contribution spec messages
Create user policy
Migrate user controller to pundit
Remove user from ability
Merge pull request #157 from neighborly/jl-pundit-contributions

Migrate contributions to Pundit
Merge pull request #164 from neighborly/jl-pundit-users

Migrate User to Pundit
Import reward policy from catarse
Add channels rights to reward policy spec
Migrate rewards controller to pundit
Migrate reward views to use pundit
Remove reward abilities
Refactor reward polity spec to use expect