We're checking return value rather than rescuing exceptions

app/models/ci/runner.rb

@@ -56,7 +56,7 @@ module Ci
     def assign_to(project, current_user = nil)
       self.is_shared = false if shared?
       self.save
-      project.runner_projects.create!(runner_id: self.id)
+      project.runner_projects.create(runner_id: self.id)
     end
 
     def display_name