How to use chruby with sudo and foreman?

Please, could you help me?
I am trying to use sudo with chruby and foreman, but without success.

I tried:

$ sudo chruby-exec ruby-2.1.2 -- foreman
$ foreman: command not found

But the same command with rake command works fine.

$ sudo chruby-exec ruby-2.1.2 -- rake --version
$ rake, version 10.1.0

Thank you very much.

I just ran $ sudo chruby-exec ruby-2.1.2 -- foreman (as user) to install the gem inside chruby root user path and it is working now.

Only to correct the before e-mail

I just ran $ sudo chruby-exec ruby-2.1.2 -- gem install foreman (as user) to install the gem inside chruby root user path and it is working now.

To install the gem inside chruby root path:

sudo chruby-exec ruby-2.1.2 -- gem install foreman

To use foreman like a root:

sudo chruby-exec ruby-2.1.2 -- foreman