use question and answer to set public port for gocd server

templates/gocd-server/0/docker-compose.yml

@@ -8,6 +8,8 @@ gocd-server:
   environment:
   - SERVER_MEM=${mem_initial}m
   - SERVER_MAX_MEM=${mem_max}m
+  ports:
+  - ${public_port}:8153
   labels:
     io.rancher.container.hostname_override: container_name
     io.rancher.sidekicks: gocd-volume

templates/gocd-server/0/rancher-compose.yml

@@ -7,6 +7,12 @@
   minimum_rancher_version: v0.59.0
   uuid: goserver-0
   questions:
+    - variable: public_port
+      description: "public port to access the gocd server"
+      label: "Public Port"
+      required: true
+      default: "8153"
+      type: "int"
     - variable: "mem_initial"
       description: "Initial java memory in Mb"
       label: "Initial memory:"
@@ -25,7 +31,7 @@
       required: true
       default: "/var/lib/docker/go-server-work"
       type: "string"
-    - variable: "volume_driver" 
+    - variable: "volume_driver"
       label: "Driver volume:"
       description: |
         Choose the volume driver to use.