fix(controller): rename destroy() to delete() and call its super()

To ensure that we destroy containers and fleet jobs when deleting an
app, do so in the Django model method delete(), not the REST API-ish
destroy() which was not connected to anything.

Author: mboersma

api/models.py

@@ -121,9 +121,10 @@ def create(self, *args, **kwargs):
         build = Build.objects.create(owner=self.owner, app=self, image=settings.DEFAULT_BUILD)
         Release.objects.create(version=1, owner=self.owner, app=self, config=config, build=build)
 
-    def destroy(self, *args, **kwargs):
+    def delete(self, *args, **kwargs):
         for c in self.container_set.all():
             c.destroy()
+        return super(App, self).delete(*args, **kwargs)
 
     def deploy(self, release):
         tasks.deploy_release.delay(self, release).get()