Assign a story to future sprint

As Patrick I want to be able to assign a story to a future sprint so that it's query-able (via sprint id).

A/C:

1. I am able to create future sprints which I can assign issues to
2. I'm able to remove future sprints and the issues are removed from them
3. I'm able to move issues between future sprints and out of future sprints and the db is updated accordingly
4. The backlog shows all future sprints, regardless of whether they are empty or not

Notes:

• as part of this, the necessary DB work to enable future sprints needs to happen

Dev Notes

Functionality that changes:

• Send to Top (from JIRA)
• Sprint dragging will not include filtered issues

Q: What happens if a sprint becomes orphaned aka all assigned boards are deleted?
A: Not Answered

Q: What if the sprint's owning board was deleted but it was visible on a second board?
A: Not Answered

Q: What if a non-visible orphaned sprint was included in the filter of a new board? Is it reassigned?
A: Not Answered

Q: What if there are multiple rank fields?
A: Not Answered

Q: Do sprints need their own rank field? If so, is it locked? What if it is deleted/modified in JIRA 5.1?
A: Not Answered

Q: What are the conditions for the migration task?
A: Not Answered

Q: What happens to sprints for which all issues have been deleted?
A: Not Answered

Q: What if an issue is assigned to more than 1 future sprint via different boards?
A: Not Answered