This is my approach on both Linux and OS X:
1) Unzip dragonruby in $HOME/opt/dragonruby, so that the dragonruby executable is $HOME/opt/dragonruby/dragonruby
2) Inside .bashrc or .zshrc add somewhere `export PATH=$PATH:$HOME/opt/dragonruby`
3) To start a new game I create an empty folder which will contain the following structure:
- app/main.rb
- run.sh
This is the `run.sh` content:
```
#!/bin/sh
dragonruby ./
```