Improve the way Release Burndown shows data

Problem Description

Release Burndown is showing data based on the timestamp with association between change items and Sprint. Below scenario will help to explain it:

1. Have a project and board
2. Create Sprint 1 and Story A
3. Assign Story A to Sprint 1 and start this Sprint
4. In Backlog, create Story B and also version 1
5. Add estimation to Story B, assign it to version 1 and complete it.
6. Notice that in Release Burndown, it displays Sprint 1 even Story B never get assigned to Sprint 1

Second scenario:

1. Have a project and board
2. Create Version 1
3. Create Sprint 1 and Sprint 2
4. Create Story A and add estimate
5. Assign Story A to Sprint 1 and start this Sprint
6. Remove Story A from Sprint 1 and assign it to Sprint 2
7. Remove Story A from Sprint 2
8. Assign Story A to Version 1 and complete this Story
9. Notice that Release Burndown shows Sprint 1 even Story A doesn't belong to this Sprint anymore when it's complete.

Suggested Resolution

Improve the way Release Burndown displays data by adding some checking if a Story belongs to certain Sprint. If it doesn't belong to any Sprint, the current Sprint should not be shown into this report.