Build/Test Tools: Enable loopback requests to work on the local development environment.

This maps `localhost` to the host machine so the requests get routed to the web server container.

Props sandrasanzdev, hasanuzzamanshamim

Fixes #52708


git-svn-id: https://develop.svn.wordpress.org/trunk@53636 602fd350-edb4-49c9-b593-d223f7449a82

docker-compose.yml

@@ -55,6 +55,9 @@ services:
     # The init directive ensures the command runs with a PID > 1, so Ctrl+C works correctly.
     init: true
 
+    extra_hosts:
+      - localhost:host-gateway
+
   ##
   # The MySQL container.
   ##
@@ -98,6 +101,9 @@ services:
     # The init directive ensures the command runs with a PID > 1, so Ctrl+C works correctly.
     init: true
 
+    extra_hosts:
+      - localhost:host-gateway
+
 volumes:
   # So that sites aren't wiped every time containers are restarted, MySQL uses a persistent volume.
   mysql: {}