allow users to setup aliases for commands

[Sasiko]

examples
!archive !a
!close !c
!reply !r

People appreciate short commands especially when there are some community that respond 30+ tickets a day.

[kyb3r]

Aliases

• Added this in v2.0.0.

If called without subcommands, returns a list of aliases that are currently set.

Subcommands

• add [name] [command]...
• del [name]

You can also pass in arguments for the command you want to link to the alias, enabling you to do things like:

• alias add i move Important