relations.rb

## DOES THIS MAKE SENSE / IS VALID

class Foo < ActiveRecord::Base
  has_many :bar
  has_many :baz, :through => :bar
end

class Bar < ActiveRecord::Base
  belongs_to :baz
end

class Baz < ActiveRecord::Base
end

##Does this make sense? Each bar only has one baz. Each foo has multiple bars. Therefore, each foo has multiple bazs, even though a bar only has one?

In Foo, you'd want plurals:
has_many :bars ;)
has_many :bazes, :through => :bars (choose a name other than baz haha ;p)

In Bar I'd add foo , so it's
belongs_to :baz
belongs_to :foo

Then in Baz you can do:
has_many :bars
has_many :foos, :through => :bars