Register StopBuilder task to be executed by builders

Author: humitos

readthedocs/builds/apps.py

@@ -17,10 +17,11 @@ def ready(self):
         app.tasks.register(ArchiveBuilds)
 
         try:
-            from readthedocsext.builds.tasks import ShutdownBuilder
+            from readthedocsext.builds.tasks import ShutdownBuilder, StopBuilder
             app.tasks.register(ShutdownBuilder)
+            app.tasks.register(StopBuilder)
         except (ModuleNotFoundError, ImportError):
-            log.info('ShutdownBuilder task could not be imported.')
+            log.info('ShutdownBuilder/StopBuilder task could not be imported.')
 
         try:
             from readthedocsext.monitoring.scaling import AutoscaleBuildersTask