expected.rb

DB.transaction do # BEGIN;
    User.new do |user|
        user.name = 'rintaun'
        user.password = 'somebullshit' # I use this for all my passwords. Oh no! Now you know! D:
        user.save # INSERT;
    end
    User.new do |user|
        user.name = 'rintaun' # this is a unique column, so this whole thing will obviously fail!
        user.password = 'areallysecurepassword'
        user.save # INSERT; -- Error
    end
end # ROLLBACK;

# SELECT COUNT(*) FROM users; -- 0

stupid_actuality.rb

DB.transaction do # BEGIN;
    User.new do |user|
        user.name = 'rintaun'
        user.password = 'somebullshit' # I use this for all my passwords. Oh no! Now you know! D:
        user.save # INSERT; COMMIT; -- LOLOL
    end
    User.new do |user|
        user.name = 'rintaun' # this is a unique column, so this whole thing will obviously fail!
        user.password = 'areallysecurepassword'
        user.save # INSERT; -- Error
    end
end # ROLLBACK; -- No transaction

# SELECT COUNT(*) FROM users; -- 1