Add basic OAuth implementation

[FranciscoDA]

This adds some basic support for OAuth authorization (#2)
Also fixes a strange bug where retweeters' ids weren't being stringified

Btw: I accidentally messed up the indentation so I reindented the whole file, sorry :/

[Rumpelcita]

Hi, why did you close this? Was it because of the indentation?

[FranciscoDA]

@Rumpelcita Sorry, I thought it wouldn't get merged. I've just reopened it 👍

[Rumpelcita]

Hey, I merged this, but when I tested it on glitch, I get the following error:

{"statusCode":401,"data":"{"errors":[{"code":32,"message":"Could not authenticate you."}]}"}

So I'm reverting the changes.

[FranciscoDA]

That's odd. Maybe it's something in the app's configuration in Twitter's developer panel? It makes sense that Twitter will refuse to give a request token if the consumer key, consumer secret or callback url are incorrect, but wouldn't an HTTP 403 status be more appropiate?

Here's my current config:

[Rumpelcita]

Okay, it seems the issue was that server.js wasn't using glitch's credentials. I fixed it, so now everything is working as it should and I added the reporting option.