Rails migration for has_and_belongs_to_many join table

Question

How do I do a script/generate migration to create a join table for a has_and_belongs_to_many relationship?

The application runs on Rails 2.

Answer 1

The top answer shows a composite index that I don't believe will be used to lookup apples from oranges.

create_table :apples_oranges, :id => false do |t|
  t.references :apple, :null => false
  t.references :orange, :null => false
end

# Adding the index can massively speed up join tables.
# This enforces uniqueness and speeds up apple->oranges lookups.
add_index(:apples_oranges, [:apple_id, :orange_id], :unique => true)
# This speeds up orange->apple lookups
add_index(:apples_oranges, :orange_id)

I did find the answer this is based on by 'The Doctor What' useful and the discussion certainly so too.