Docs - update with port of gateway

guide/asynchronous.md

@@ -3,16 +3,16 @@
 Asynchronous function calls can be queued up using the following route:
 
 ```
-$ curl --data "message" http://gateway/async-function/{function_name}
+$ curl --data "message" http://gateway:8080/async-function/{function_name}
 ```
 
 Summary of modes for calling functions via API Gateway:
 
 | Mode         | Method | URL                                            | Body | Headers  | Query string
 | -------------|--------|------------------------------------------------|------|--------- |------------------- |
-| Synchronous  | POST   | http://gateway/function/{function_name}        | Yes  | Yes      | Yes |
-| Synchronous  | GET    | http://gateway/function/{function_name}        | Yes  | Yes      | Yes |
-| Asynchronous | POST   | http://gateway/async-function/{function_name}  | Yes  | Yes      | Yes [#369](https://github.com/openfaas/faas/issues/369) |
+| Synchronous  | POST   | http://gateway:8080/function/{function_name}        | Yes  | Yes      | Yes |
+| Synchronous  | GET    | http://gateway:8080/function/{function_name}        | Yes  | Yes      | Yes |
+| Asynchronous | POST   | http://gateway:8080/async-function/{function_name}  | Yes  | Yes      | Yes [#369](https://github.com/openfaas/faas/issues/369) |
 | Asynchronous | GET    | Not supported                                  | -    | -        | - |
 
 This work was carried out under [PR #131](https://github.com/openfaas/faas/pull/131).
@@ -61,15 +61,17 @@ $ kubectl -f apply ./faas.async.yml,nats.yml
 Functions do not need to be modified to work asynchronously, just use this alternate route:
 
 ```
-http://gateway/async-function/{function_name}
+http://gateway:8080/async-function/{function_name}
 ```
 
 If you want the function to call another function or a different endpoint when it is finished then pass the `X-Callback-Url` header. This is optional.
 
 ```
-$ curl http://gateway/async-function/{function_name} --data-binary @sample.json -H "X-Callback-Url: http://gateway/function/send2slack"
+$ curl http://gateway:8080/async-function/{function_name} --data-binary @sample.json -H "X-Callback-Url: http://gateway:8080/function/send2slack"
 ```
 
+You can also use the following site to setup a public endpoint for testing HTTP callbacks: [requestb.in](https://requestb.in)
+
 ## Extend function timeouts
 
 Functions have three timeouts configurable by environmental variables expressed in seconds: