title: Forking shipping app has no effect in Django oscar
body: <p>I had forked my shipping app into a folder called forked_apps using oscar_fork_app command and also added in settings.py get_core_apps(['forked_apps.shipping']), I just want to create two shipping methods mentioned, standard and express in the docs in this link:<a href="https://django-oscar.readthedocs.io/en/latest/howto/how_to_configure_shipping.html" rel="nofollow noreferrer">https://django-oscar.readthedocs.io/en/latest/howto/how_to_configure_shipping.html</a>.</p>
  
  <p>In the <strong>init</strong>.py I have this code pre-existing:</p>
  
  <pre><code>default_app_config = 'forked_apps.shipping.config.ShippingConfig'
  </code></pre>
  
  <p>In repository.py I have written like this:</p>
  
  <pre><code>from oscar.apps.shipping import repository
  from .methods import *
  
  
  class Repository(repository.Repository):
  
      def get_available_shipping_methods(
              self, basket, user=None, shipping_addr=None,
              request=None, **kwargs):
          methods = (Standard())
          print("\n\nFetch availble shipping methods")
          if shipping_addr:
              # Express is only available in the UK
              methods = (Standard(), Express())
  
          return methods
  </code></pre>
  
  <p>And in the methods.py I had written:</p>
  
  <pre><code>from decimal import Decimal as D
  from oscar.apps.shipping import methods
  from oscar.core import prices
  
  class Standard(methods.FixedPrice):
      code = 'standard'
      name = 'Standard shipping'
      charge_excl_tax = D('5.00')
  
  class Express(methods.FixedPrice):
      code = 'express'
      name = 'Express shipping'
      charge_excl_tax = D('10.00')
  </code></pre>
  
  <p>What should happen is, the shipping_methods.html page should show up, but instead, after entering the shipping address it goes to the payment details page directly; this would usually happen only if there are no shipping methods defined, but I have implemented two shipping methods, standard and Express in the above code.I can't figure out how to make this work, even the print statement isn't working.
  Is there any other additional code that I must write?</p>
  
  <p>Can someone provide a solution with some code, if you have implemented it?</p>