Add UserAssignmentTask entity and update task assignment logic#37

NKSurprise wants to merge 3 commits intodevDEVids-VT/SkillBridge-API:devfrom

34-move-task-completion-tracking-from-assignmenttask-to-userprojectassignment-for-per-user-task-statusDEVids-VT/SkillBridge-API:34-move-task-completion-tracking-from-assignmenttask-to-userprojectassignment-for-per-user-task-statusCopy head branch name to clipboard