Change asyncData Functions to promise for more concise syntax.

I think this function is better as a promise.
```suggestion
asyncData = (context) => new Promise((resolve, reject) => {
context.$axios.$get('auth/discord/redirect')
.then(result => resolve(result))
.catch(reason => reject(reason))
})
```

_Originally posted by @Soliel in https://github.com/crybapp/web/diffs_