code: function(code, url, done) {
    try {
      require('vm').runInThisContext(code, url)
      done()
    } catch (e) {
      done(e)
    }
  }
docs: Executes the given code in the current environment / scope, runs
  the corresponding callback when done
  
  @param {String} code to execute
  @param {String} url of the script (for displaying the stack)