If you want to install rabbitmq plugins on Ubuntu 12.04 you can do this with:
/usr/lib/rabbitmq/lib/rabbitmq_server-2.7.1/sbin/rabbitmq-plugins
Rails LTS provides security patches for old versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2)
This binary is not in your default $PATH. Beause of this you have to give the full path.