webhooks/gci: Support 'needswork' event_type.

This commit adds support for payloads that are generated when a
mentor submits a task for more work.

zerver/webhooks/gci/fixtures/task_submitted_by_mentor_for_more_work.json

@@ -0,0 +1,12 @@
+{
+    "task_definition_url":"http://localhost:8080/dashboard/tasks/6051711999279104/",
+    "task_claimed_by":"student-yqqtag",
+    "event_type":"needswork",
+    "author":"eeshangarg",
+    "task_instance_url":"http://localhost:8080/dashboard/task-instances/6051711999279104/",
+    "task_definition_name":"Sails unspread it stopped at kearney",
+    "time":1509576007.257213,
+    "id":"19f30988c86045bfbc6aacd789cd3a92",
+    "task_instance":5136918324969472,
+    "author_is_student":false
+}

zerver/webhooks/gci/tests.py

@@ -43,3 +43,10 @@ class GoogleCodeInTests(WebhookTestCase):
         expected_message = u'**eeshangarg** approved the task [Sails unspread it stopped at kearney](https://0.0.0.0:8000/dashboard/tasks/6694926301528064/).'
         self.send_and_test_stream_message('task_approved_by_mentor',
                                           expected_subject, expected_message)
+
+    def test_needswork_event_message(self):
+        # type: () -> None
+        expected_subject = u'Task: Sails unspread it stopped at kearney'
+        expected_message = u'**eeshangarg** submitted the task [Sails unspread it stopped at kearney](http://localhost:8080/dashboard/tasks/6051711999279104/) for more work.'
+        self.send_and_test_stream_message('task_submitted_by_mentor_for_more_work',
+                                          expected_subject, expected_message)

zerver/webhooks/gci/view.py

@@ -59,6 +59,15 @@ def get_approve_event_body(payload):
         task_url=payload['task_definition_url'],
     )
 
+def get_needswork_event_body(payload):
+    # type: (Dict[Text, Any]) -> Text
+    template = "{} for more work.".format(GCI_MESSAGE_TEMPLATE.rstrip('.'))
+    return template.format(
+        actor=payload['author'],
+        action='submitted',
+        task_name=payload['task_definition_name'],
+        task_url=payload['task_definition_url'],
+    )
 
 @api_key_only_webhook_view("Google-Code-In")
 @has_request_variables
@@ -78,10 +87,11 @@ def api_gci_webhook(request, user_profile, stream=REQ(default='gci'),
 
 EVENTS_FUNCTION_MAPPER = {
     'abandon': get_abandon_event_body,
-    'comment': get_comment_event_body,
-    'submit': get_submit_event_body,
-    'claim': get_claim_event_body,
     'approve': get_approve_event_body,
+    'claim': get_claim_event_body,
+    'comment': get_comment_event_body,
+    'needswork': get_needswork_event_body,
+    'submit': get_submit_event_body,
 }
 
 def get_event(payload):