Transition to creating tasks with POST method rather than GET.

GET will be removed once we have a functioning button that does POST.

attract/tasks.py

@@ -60,7 +60,8 @@ def save(project, task_id):
     return flask.jsonify({'task_id': task_id, 'etag': task._etag})
 
 
-@blueprint.route('/<project_url>/create')
+# TODO: remove GET method once Pablo has made a proper button to call this URL with a POST.
+@blueprint.route('/<project_url>/create', methods=['POST', 'GET'])
 @attract_project_view()
 def create_task(project):
     task = current_task_manager.create_task(project)