Add volumes to marathon file.

docker/marathon.json

@@ -9,6 +9,23 @@
     "docker": {
       "network": "HOST",
       "image": "sytse/gitlab-ce:7.10.1"
+    },
+    "volumes": [
+      {
+          "containerPath": "/etc/gitlab",
+          "hostPath": "/var/data/etc/gitlab",
+          "mode": "RW"
+      },
+      {
+          "containerPath": "/var/opt/gitlab",
+          "hostPath": "/var/data/opt/gitlab",
+          "mode": "RW"
+      },
+      {
+          "containerPath": "/var/log/gitlab",
+          "hostPath": "/var/data/log/gitlab",
+          "mode": "RW"
       }
+    ]
   }
 }
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