text: exports.up = function(knex) {
      return knex.schema.createTable('comments', tbl => {
          tbl.increments();
          tbl.string('description', 1000)
              .notNullable();
          tbl.integer('author_id')
              .notNullable()
              .unsigned()
              .references('id')
              .inTable('users')
              .onUpdate('CASCADE')
              .onDelete('CASCADE');
          tbl.timestamp('created_at')
              .notNullable()
              .defaultTo(knex.fn.now());
      })
  };
  
  exports.down = function(knex) {
      return knex.schema.dropTableIfExists('comments');
  };
  