fix mock mode example

hrldcpr · HarishRaj11 · commit 7b85b7e2774d · 2019-04-08T14:52:11.000+05:30
The given example doesn't actually work, as discussed in #342
diff --git a/docs/mock-mode.md b/docs/mock-mode.md
@@ -42,6 +42,7 @@ produces:
   - application/json
 paths:
   /weather:
+    x-swagger-router-controller: weather
     get:
       responses:
         "200":
