Cant Debug on OSX

RubyMine 2018.1.4

MacOS 10.13.5

I can't install ruby-debug-ide-0.6.1.gem in the standard location (/usr/bin) because that directory is protected even running sudo:

ERROR: While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /usr/bin directory.

So I installed it in /usr/local/bin (with the -n switch)

$ gem list ruby-debug-ide

*** LOCAL GEMS ***

ruby-debug-ide (0.6.1)

Now how do I get RubyMine to recognize it?