No need to create Twitter apps by ourselves

[yutannihilation]

As of rtweet version 0.6.0, we can play with the app already registered by the package author. I've confirmed here: https://github.com/mkearney/rtweet/issues/167

So, the description on Recipe 1 is a bit outdated today. Of course, if you would describe about actions that need more permission than read-only, creating own app is necessary. But, it seems not. Is it possible to omit the part about creating a new application?