Updated Lua Examples (markdown)

Lua-Examples.md

@@ -2,8 +2,9 @@ By default Inbucket will load `inbucket.lua`, but you may use the `INBUCKET_LUA_
 
 ## Event trigger: after message stored
 
+Prints metadata of stored messages to STDOUT.
+
 ```lua
--- Prints metadata of stored messages to STDOUT.
 function inbucket.after.message_stored(msg)
   print("\n## message_stored ##")
 
@@ -20,3 +21,24 @@ function inbucket.after.message_stored(msg)
   print(string.format("subject: %s", msg.subject))
 end
 ```
+
+Makes a JSON encoded POST to a web service.
+
+```lua
+local http = require("http")
+local json = require("json")
+
+BASE_URL = "https://myapi.example.com"
+
+function inbucket.after.message_stored(msg)
+  local request = json.encode {
+    subject = string.format("Mail from %q", msg.from.address),
+    body = msg.subject
+  }
+
+  assert(http.post(BASE_URL .. "/notify/text", {
+    headers = { ["Content-Type"] = "application/json" },
+    body = request,
+  }))
+end
+```