Add all internal IPs for multiple docker networks (cookiecutter#1520)

* Add all internal IPs for multiple docker networks

When developing with modified docker-compose.yml that contains multiple
network definitions, all networks gateways of the created container
should be added to INTERNAL_IPS, otherwise Django-Debug-Toolbar will not
work.

* Add @flyudvik to contributors

Author: flyudvik

CONTRIBUTORS.rst

@@ -116,6 +116,7 @@ Listed in alphabetical order.
   Luis Nell                `@originell`_
   Lukas Klein
   Lyla Fischer
+  Malik Sulaimanov         `@flyudvik`_                  @flyudvik
   Martin Blech
   Mathijs Hoogland         `@MathijsHoogland`_
   Matt Braymer-Hayes       `@mattayes`_                  @mattayes
@@ -196,6 +197,7 @@ Listed in alphabetical order.
 .. _@eraldo: https://github.com/eraldo
 .. _@eriol: https://github.com/eriol
 .. _@eyadsibai: https://github.com/eyadsibai
+.. _@flyudvik: https://github.com/flyudvik
 .. _@garry-cairns: https://github.com/garry-cairns
 .. _@garrypolley: https://github.com/garrypolley
 .. _@goldhand: https://github.com/goldhand

{{cookiecutter.project_slug}}/config/settings/local.py

@@ -64,8 +64,8 @@
 import socket
 import os
 if os.environ.get('USE_DOCKER') == 'yes':
-    ip = socket.gethostbyname(socket.gethostname())
-    INTERNAL_IPS += [ip[:-1] + '1']
+    hostname, _, ips = socket.gethostbyname_ex(socket.gethostname())
+    INTERNAL_IPS += [ip[:-1] + '1' for ip in ips]
 {%- endif %}
 
 # django-extensions