GAM: GAM install doesn't install in ZSH (or other shells)

Full steps to reproduce the issue:

1. Install GAM as per wiki
2. Restart ZSH

Expected outcome (what are you trying to do?): GAM command will be available

Actual outcome (what errors or bad behavior do you see instead?): GAM command is not available

The appears to append gam() { "/home/dmills/bin/gam/gam" "$@" ; } to the .bashrc file to load the gam command. However zsh and other popular shells don’t use .bashrc file. GAM should check what shell is running and append it in the appropriate file for at least common shell options.