Enable milestones to be assigned to users
Currently, milestones exist at a project or group level with the only way to sort them being "Open", "Closed", and "All". On our teams, we have milestone owners, but the interface does not support this. Presently, we put the username in "()" at the end of the milestone title.
Allow milestones to have an owner such that the interface allows a user to quickly see which milestones they own quickly. Possibly related but separate, a default user milestone page might show the milestones that they own, and in a second section, display milestones that include issues that are assigned to the user.