Feature/redirect successful post requests#56

Created by: wasabideveloper

Implements enhancement #56 (closed)

• ran check
• ran tests
• ran flake8
• tested views by hand:
  • /orders/new#existing_excerpt [get]
  • /orders/new [post]
  • /orders/{id} [get]

Reviewed by:

• @das-g
• @njordan-hsr