Introducing the event timeline

The api calls will now create events with a 'event_type' set to an
action that was performed.
Regular user comments will now also have their own type.

TimeLine Events have an optional reference to a comment (comment_id). If
comment_id is set then a comment_field will be resolved to bring the
content of the comment along with the event in one response.

The event_info field contains additional information about the event
which now includes:
* task_title
* old/new_status
* old/new_assignee_name

This information shouild be helpfull for UI to render the event w/o
making additional requests to the server-side.

Change-Id: I2ad04dbe47c249ee06d9753a164a597889c810b9

storyboard/common/event_resolvers.py

@@ -0,0 +1,72 @@
+# Copyright (c) 2014 Mirantis Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import json
+
+from storyboard.db.api import users as users_api
+
+
+def story_created(event):
+    return event
+
+
+def story_story_details_changed(event):
+    return event
+
+
+def user_comment(event):
+    return event
+
+
+def task_created(event):
+    return event
+
+
+def task_status_changed(event):
+    return event
+
+
+def task_assignee_changed(event):
+    event_info = json.loads(event.event_info)
+
+    old_assignee_id = event_info["old_assignee_id"]
+    old_assignee = users_api.user_get(old_assignee_id)
+    if old_assignee:
+        old_fullname = old_assignee.full_name
+    else:
+        old_fullname = "unassigned"
+    event_info["old_assignee_fullname"] = old_fullname
+
+    new_assignee_id = event_info["new_assignee_id"]
+    new_assignee = users_api.user_get(new_assignee_id)
+    if new_assignee:
+        new_fullname = new_assignee.full_name
+    else:
+        new_fullname = "unassigned"
+    event_info["new_assignee_fullname"] = new_fullname
+
+    event.event_info = json.dumps(event_info)
+    return event
+
+
+def task_details_changed(event):
+    return event
+
+
+def task_deleted(event):
+    #NOTE: There is nothing to resolve, as the task title is already stored in
+    # the info. There is no way to store an id because the task is hard deleted
+    # at the moment we would query it.
+    return event