environment.js

if (deployTarget === 'development') {
  ENV['ember-cli-mirage'] = { enabled: process.env.WITH_MIRAGE || false };
}

package.json

{
 "scripts": {
   "mirage": "./scripts/run -m"
 }
}

run

#!/bin/bash

echo -n -e "\033]0;Ember\007";

subdomain=""
mirage=""

while getopts d:m opts; do
  case $opts in
    d) subdomain="DOKI_SUBDOMAIN=$OPTARG "  ;;
    m) mirage="WITH_MIRAGE=true "           ;;
  esac
done

run_command="${subdomain}${mirage}ember server"

echo "Running \"${run_command}\"..."
eval $run_command

echo -n -e "\033]0;\007";