multer is writing to `ctx.req` instead of `ctx.request`

I think multer should write to ctx.request because that is the koa request object currently it is writing to the ctx.req which is the original node request object.

In my opinion this change would align the behaviour of this module with the koa ecosystem.

[raphaelsoul]

on my side, those below are always undefined:

• ctx.request.files
• ctx.request.file
• ctx.req.file
• ctx.req.files

the configuration like this:

import multer from 'koa-multer'
import bodyparser from 'koa-bodyparser'
const upload = multer({ dest: '/path/to/tmp' })

//use it globally
app.use(multer.any())
app.use(bodyparser())

I tried postman and html form with enctype="multipart/form-data", both had saved file with hashed name but I can’t access to file infomation via ctx

the version is koa-multer@1.0.1 and koa@2.2.0.

Weired

[i5ting]

@fundon can be merge that pr?