code: function buildURL(dbName, opts) {
    var authentication
    opts.scheme = opts.scheme || 'http'
    opts.host   = opts.host   || '127.0.0.1'
    opts.port   = opts.port   || '5984'
  
    if (has(opts, 'auth')) {
      if (typeof opts.auth === 'object') {
        authentication = opts.auth.username + ':' + opts.auth.password + '@'
      }
    }
  
    return opts.scheme + '://' + authentication + opts.host + ':' + opts.port + '/' + dbName
  }
docs: Build the URL to push CouchApp.
  
  @param  {String} dbName
  @param  {Object} opts
  @return {String}