USER STORY; Manage bookings as Site Admin

[hysinh]

As a Site admin, I can create and manage any booking so that I can manage the bookings for the venue

• [x] AC1 Given that I am the site admin with the proper credentials, I can view all of the bookings made by all the customers.
• [x] AC2 Given that I am the site admin, I can approve or cancel a booking request

[hysinh]

Tasks - Build the Booking model

• [x] Add attributes to the booking model
• [x] migrate
• [x] import model to admin.py
• [x] Test as superuser
• [x] Manual deployment to Heroku
• [x] include ordering so that booking are listed in order of Event date

Tasks - Set up the superuser

• [x] Create superuser admin account