To my knowledge, placing `bash_completion` files in `/etc/bash_completion.d` causes them to automatically be sourced if `bash_completion` is enabled (set up in `.bashrc`). It does currently require `sudo` to install. 

The `bash_completion.sh` file could also be placed in the `$HOME` directory and something like `. ~/.git-pluck` could be added to the `.bashrc`. I can make a note of this in the `README`.