Allow a string to be passed as the port config option (#766)

Author: SpaceK33z

lib/optionsSchema.json

@@ -34,7 +34,14 @@
     },
     "port": {
       "description": "The port the server listens to.",
-      "type": "number"
+      "anyOf": [
+        {
+          "type": "number"
+        },
+        {
+          "type": "string"
+        }
+      ]
     },
     "socket": {
       "description": "The Unix socket to listen to (instead of on a host).",