Unable to alter more than one column in the same alter statement

[jameswilddev]

This works:

    migrate() {
        this.alter('site_map_pages', blueprint => {
            blueprint.integer('width').required().default(0);
        });
    }

    // In another migration...

    migrate() {
        this.alter('site_map_pages', blueprint => {
            blueprint.integer('height').required().default(0);
        });
    }

This doesn't (only the width column is added):

    migrate() {
        this.alter('site_map_pages', blueprint => {
            blueprint.integer('width').required().default(0);
            blueprint.integer('height').required().default(0);
        });
    }

It looks like under the hood this generates a single string with multiple ALTER TABLE statements in it which probably isn't supported.