drop column adonisjs migration

1down () {
2    //Remove Default Value Constraint
3    this.alter('mytable', (table) => {
4      table.boolean('column1')
5      table.boolean('column2')
6    })
7
8    //Remove Columns
9    this.alter('mytable', (table) => {
10      table.dropColumn('column1')
11      table.dropColumn('column2')
12    })
13  }
14