rails:freeze:gems missing

I am trying to freeze gems I get:

rake rails:freeze:gems
rake aborted!
Don't know how to build task 'rails:freeze:gems'

(See full trace by running task with --trace)

I also cant find rails:freeze:gems when i do rake -T
I am new to Ruby so I am not sure where to begin.
Any suggestions?

Hai!

  http://support.tigertech.net/freeze-rails

Bye:)
bdeveloper01