move find cron for repository to query

lib/travis/api/v3/queries/crons.rb

@@ -1,6 +1,10 @@
 module Travis::API::V3
   class Queries::Crons < Query
 
+    def find(repository)
+      Models::Cron.where(:branch_id => repository.branches)
+    end
+
     def start(branch)
       raise ServerError, 'repository does not have a github_id'.freeze unless branch.repository.github_id
 

lib/travis/api/v3/services/crons/for_repository.rb

@@ -3,7 +3,7 @@ module Travis::API::V3
     paginate
 
     def run!
-      Models::Cron.where(:branch_id => find(:repository).branches)
+      query.find(find(:repository))
     end
   end
 end