Add models for the protected branch access levels.

- And hook up their associations.

app/models/protected_branch.rb

@@ -5,6 +5,9 @@ class ProtectedBranch < ActiveRecord::Base
   validates :name, presence: true
   validates :project, presence: true
 
+  has_one :merge_access_level
+  has_one :push_access_level
+
   def commit
     project.commit(self.name)
   end

app/models/protected_branch/merge_access_level.rb

+class ProtectedBranch::MergeAccessLevel < ActiveRecord::Base
+  belongs_to :protected_branch
+end

app/models/protected_branch/push_access_level.rb

+class ProtectedBranch::PushAccessLevel < ActiveRecord::Base
+  belongs_to :protected_branch
+end