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

        roads
            .integer('start_city_id')
            .unsigned()
            .notNullable()
            .references('id')
            .inTable('cities')
            .onDelete('CASCADE')
            .onUpdate('CASCADE');

        roads
            .integer('end_city_id')
            .unsigned()
            .notNullable()
            .references('id')
            .inTable('cities')
            .onDelete('CASCADE')
            .onUpdate('CASCADE');

        roads
            .integer('distance')
            .unsigned()
            .notNullable()
    });
};

exports.down = function(knex) {
    return knex.schema.dropTableIfExists('roads');
};