code: function syncSchema(result, schema) {
    var knex = this.knex;
    return knex.schema.hasTable(schema.tableName)
    .then(function (exists) {
      if (exists) return result;
      return knex.schema.createTable(schema.tableName, defineSchemaTable(schema))
      .then(function () {
        return result.concat([schema]);
      });
    });
  }
docs: Synchronize given schema with database.
  
  @param {[Schema]} result - reduce accumulator
  @param {Schema} schema
  @return {Promise}