Story events may now be filtered by event_type.

The /stories/:id/events endpoint now accepts a list of event types
as filter parameters. Models have been updated to treat event types
as enums, for proper query construction. Tests have been provided.

DB Base has been updated to remove enum special casing, and instead
treat all list() values as WHERE IN logic. This should also assist
with the speed of strict equality tests.

Change-Id: Iea2c941f1e5e9a25c9e0631aaa6a750a93b3e848

storyboard/common/event_types.py

@@ -4,7 +4,7 @@
 # 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
+# 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,
@@ -28,3 +28,16 @@ TASK_STATUS_CHANGED = "task_status_changed"
 TASK_PRIORITY_CHANGED = "task_priority_changed"
 TASK_ASSIGNEE_CHANGED = "task_assignee_changed"
 TASK_DELETED = "task_deleted"
+
+ALL = (
+    STORY_CREATED,
+    STORY_DETAILS_CHANGED,
+    STORY_DETAILS_CHANGED,
+    USER_COMMENT,
+    TASK_CREATED,
+    TASK_ASSIGNEE_CHANGED,
+    TASK_DETAILS_CHANGED,
+    TASK_STATUS_CHANGED,
+    TASK_PRIORITY_CHANGED,
+    TASK_DELETED
+)