add_reference

Adds a reference. Optionally adds a type column, if :polymorphic option is provided. add_reference and add_belongs_to are acceptable.

Create a user_id column

add_reference(:products, :user)

Create a supplier_id and supplier_type columns

add_belongs_to(:products, :supplier, polymorphic: true)

Create a supplier_id, supplier_type columns and appropriate index

add_reference(:products, :supplier, polymorphic: true, index: true)

add_belongs_to