exports.up = function (knex) {
    // Add new column heartbeat.end_time
    return knex.schema.alterTable("heartbeat", function (table) {
        table.datetime("end_time").nullable().defaultTo(null);
    });
};

exports.down = function (knex) {
    // Rename heartbeat.start_time to heartbeat.time
    return knex.schema.alterTable("heartbeat", function (table) {
        table.dropColumn("end_time");
    });
};
