Using Caps Lock as mod key
I would like to use Caps Lock as my mod key. The only reference to Caps Lock I can find is in the User Guide:
Unlike other window managers, i3 can use Mode_switch as a modifier. This allows you to remap capslock (for example) to Mode_switch and use it for both: typing umlauts or special characters and having some comfortably reachable key bindings. For example, when typing, capslock+1 or capslock+2 for switching workspaces is totally convenient. Try it :-).
But I still don't understand how it can be accomplished. So how can I do it?