add attachment support on top of v0.1.4

[nanaeasiedu]

This adds attachment support.

[geekgonecrazy]

lgtm thanks @ngenerio !

[geekgonecrazy]

@ngenerio can you give us an example on how you'd use this? I'd like to add it to our documentation.

[nanaeasiedu]

@geekgonecrazy Sure. When a user sends a message to hubot prior to this pull request, there was no way to get information concerning the attachment. The message.text was undefined.

Now, you can simply do this:

robot.respond /some string/, (resp) ->
  if resp.message.attachment?
    {attachment} = resp.message
    console.log attachment.type, attachment.link
    # or probably store it in hubot's brain

to know if there was an attachment to the message and perform some action based on that. I hope this helps.