Flow error

[entropitor]

I get the next flow error using this library:

node_modules/koa-graphql/dist/index.js.flow:164
164:       req.body = req.body || request.body;
               ^^^^ property `body`. Property not found in
164:       req.body = req.body || request.body;
           ^^^ http$IncomingMessage

[tryshchenko]

Fixed in #109