Allow to use command aliases

[nir0s]

It would be nice to run

ghost rm key instead of ghost delete key, for instance.
Also, ghost put -> ghost write and ghost get -> ghost read

Reference:
http://click.pocoo.org/6/advanced/#command-aliases
https://github.com/click-contrib/click-aliases

[nir0s]

I'm going to close this as it might actually be better not to confuse people :)