option to disable colors

[stephenmathieson]

they're just noise outside of development. i'd rather not have to pipe my logs through something to remove ansi escape sequences in order to view them.

maybe we could add something like:

const logger = getLoggerSomehow()
const logMiddleware = require('winston-koa-logger')

app.use(logMiddleware(logger, {
  disableColors: true
}))

or better yet, internally, we could say:

const shouldUseColors = tty.isatty(X) && process.env.NODE_ENV !== 'production'

so that apps didn't have to disable this stuff upstream ;)