title: Sequelize js , how do we change column type in migration
body: <p>how do we change column type in migration. In my migration 1 I have a migration that added the column. Now I want to change the column type from string to text , should I create a new migration file which is like changeColumn or I can create new migration file the same with migration 1 but I have just to change the type to text ? Thank you.</p>
  <p>#Migration 1</p>
  <pre><code>await queryInterface.addColumn(SampleModel.tableName, 'name', {
    type: Sequelize.STRING,
    allowNull: true,
  }, {
    transaction,
  });
  </code></pre>
  <h1>Migration 2 (does creating new migration would work like this ? still addColumn but i change the type to text)</h1>
  <pre><code>  await queryInterface.addColumn(SampleModel.tableName, 'name', {
        type: Sequelize.TEXT,
        allowNull: true,
      }, {
        transaction,
      });
  </code></pre>