Install shell-completion provided by hledger

[Jakob Schöttl]

Hi all,

Would the package maintainer for the hledger package add some lines to 
install the bash completion script for the next release of hledger?

The source code of hledger has the file 
shell-completion/hledger-completion.bash

It's in https://github.com/simonmichael/hledger/tree/master/shell-completion

Can this be installed into /etc/bash_completion.d or 
/usr/local/etc/bash_completion.d (I'm not sure how this is normally done)?

Thank you!

- Jakob