exports.up = function(knex) {
    return knex.schema.createTable('cities', function(cities) {
      cities.increments();

      cities.string('name', 128).notNullable();
      cities
        .integer('country_id')
        .unsigned()
        .notNullable()
        .references('id')
        .inTable('countries')
        .onDelete('CASCADE')
        .onUpdate('CASCADE');
    });
  };
  
  exports.down = function(knex) {
    return knex.schema.dropTableIfExists('cities');
  };