Merge branch 'develop'

README.md

@@ -97,12 +97,21 @@ The entrypoint is responsible for:
 
 ### How to add additional hostnames?
 
-If you want to test hosts not configured in the web container, you need to use external_links in
-[docker-compose.backstop.yaml](docker-compose.backstop.yaml).
+If you want to test hosts not configured in the web container, you need to use external_links in the service containers. 
+For that add a file `docker-compose.external_links.yaml` to your project which should look like this:
+
+```yaml
+services:
+  chrome: &domains
+    external_links:
+      - "myproject.ddev.site:myproject"
+      - "myproject2.ddev.site:myproject2"
+  firefox:
+    <<: *domains
+```
 
 See: [ddev FAQ: Can different projects communicate with each other?](https://ddev.readthedocs.io/en/latest/users/usage/faq/#features-requirements)
 
-Do not forget to remove the #ddev-generated line!
 
 ### Change backstop tests directory
 Per default the backstop directory containing backstop config etc. is expected in your project directory (besides the