Add RestaurantShifts helper class
Add :with_shifts_this_week scope to Restaurants model
Add Shifts#build_clone_week_preview
Add view for Shifts #preview_clone_week
Add datetimepicker to shifts#preview_clone_week (finish specs for  #preview_clone)
Add #increment_week to RestaurantShifts, use in #preview_clone_week
Add Shifts #save_clone_week
add jQuery for adding, removing shifts in Shifts #save_clone_week
Refactor jQuery in #preview_clone_week (add event handler clearing after each recursion)
re-refactor jQuery for #preview_clone_week
Refactor js for #preview_clone_week (create separate World, Mutator, and Listener classes)
Add Mutator.editShift to #preview_clone_week JS
Add error-handling to Shifts #preview_clone_week
Finish tests for basic #clone_week save, Add database_cleaner gem, begin testing shift addition js in #preview_clone_week
Add specs for adding, removing, and editing shift in #preview_clone_week
Add specs for error-handling in #preview_clone_week
Add link to #build_clone_week_preview to nav bar
BUG FIX: add missing association building to #clone_week batch save