Why does it say bundler not installed after i install bundler?

I have rbenv and a few rubies installed. On my 1.9.3-p484 i'm trying to install bundler. I seem to install it....but it does not show up. I get this error...

fonso@mybox:~/my-dev$ gem install bundler -v '1.0.22'
Successfully installed bundler-1.0.22
1 gem installed
Installing ri documentation for bundler-1.0.22...
Installing RDoc documentation for bundler-1.0.22...
fonso@mybox:~/my-dev$ bundler --version
rbenv: bundler: command not found

The `bundler' command exists in these Ruby versions:
  2.3.0
  2.4.4
  2.5.8

fonso@mybox:~/my-dev$

How can I fix this?