add reuse identifier for details uitableview cells
implement UITableViewController methods
add new icon images
add icon for customers counter table cells
adjust Customer counter button icon
Add CoreData properties in DetailViewController and implement NSFetchedResultsControllerDelegate methods
Implement counter when user taps on a clients group
add Podfile
send ManagedObjectContext to detail view on picking campaign
remove sending Campaign object to detail view
add managedObjectContext setter in detail controller; insert object when user picks a customer group from the detail view