title: How to add incremental column type float in Ruby on Rails with Postgresql
body: <blockquote>
    <p>I am adding a new column to table but I wanted to be its
    auto_increment with float type. I am using postgresql, I don't know
    how to do please suggest below is the migration</p>
  </blockquote>
  
  <pre><code>class AddPositionToItems &lt; ActiveRecord::Migration[5.0]
    def change
      add_column :items, :position, :float
    end
  end
  </code></pre>