Add selenium containers that can be used for e.g. Behat tests

templates/docker-compose.yml.twig

@@ -208,6 +208,45 @@ services:
       - files:/mnt/files
 {% endif %}
 
+  hub:
+    image: 'elgalu/selenium'
+    volumes:
+      - /dev/shm:/dev/shm
+    privileged: true
+    environment:
+      - SELENIUM_HUB_HOST: 'hub'
+      - SELENIUM_HUB_PORT: '4444'
+      - GRID: 'true'
+      - CHROME: 'false'
+      - FIREFOX: 'false'
+    depends_on:
+      - php
+
+  chrome:
+    image: 'elgalu/selenium'
+    depends_on:
+      - hub
+    volumes:
+      - /dev/shm:/dev/shm
+    privileged: true
+    environment:
+      - NOVNC: 'true'
+      - SELENIUM_HUB_HOST: 'hub'
+      - SELENIUM_HUB_PORT: '4444'
+      - SELENIUM_NODE_HOST: '{{ docker0.ip }}'
+      - SCREEN_WIDTH: '1300'
+      - SCREEN_HEIGHT: '999'
+      - VIDEO: 'false'
+      - GRID: 'false'
+      - CHROME: 'true'
+      - FIREFOX: 'false'
+    #ports:
+      # VNC: See what's going on by connecting your VNC client to 0.0.0.0:5900
+      #- 5900:25900
+      # noVNC: See what's going on by hitting http://0.0.0.0:6080 in your browser
+      #        Important: http://127.0.0.1:6081 works but http://localhost:6081 doesn't
+      #- 6080:26080
+
 networks:
   default:
     external: