how to configure charge in your app.coffee file

app.coffee

charge_config = require './config.json'

module.exports =
  # the rest of your roots configuration stuff
  
  # this reads your config.json and configures charge
  server: charge_config
  
  # alternately you could define your key/values inline
  # server: 
  #   clean_urls: true
  #   spa: true
  #   log: 'tiny'
  #   error_page: 'error.html'

config.json

{
  "clean_urls": true,
  "spa": true,
  "error_page": "error.html",
  "gzip": true,
  "log": "tiny"
}