Add bang-bang script.

src/scripts/bang-bang.coffee

@@ -0,0 +1,18 @@
+# !! - Repeat the last command directed at hubot
+module.exports = (robot) ->
+  robot.respond /(.+)/i, (msg) ->
+    store msg
+
+  robot.respond /!!/i, (msg) ->
+
+    if exports.last_command?
+      msg.send exports.last_command
+      msg['message']['text'] = "hubot: #{exports.last_command}"
+      robot.receive(msg['message'])
+      msg['message']['done'] = true
+    else
+      msg.send "i don't remember hearing anything."
+
+store = (msg) ->
+  command = msg.match[1].trim()
+  exports.last_command = command unless command == '!!'