Add Commands Abbreviations

[Exper1mental]

Got the idea while figuring out how to squash commits in Git Bash.

The following do the same thing:

git rebase -i 60042c8

git rebase --interactive 60042c8

My idea is to apply this same concept to commands we use with the bot. The (obvious) benefit is being able to reduce the typing required for commands while preserving the longer, more descriptive command names as well.

Example:

$ role add Junior

Could also be called using

$ -r -a Junior

or something like that.

Ideally we'd want to agree on a naming system for the abbreviations

Would tie in well with updating the help command (#127)

[Jay-Madden]

This is easily accomplished by just adding an alias in the command decorator, see the assignables roles cog or the designated channels cog for an example