Add kredis_boolean attribute with default argument

[MrHubble]

Add kredis_boolean. Follows in the same vein of existing attributes (e.g. kredis_integer). The only difference being I added default as an argument:

kredis_boolean :noodling, default: false

[kaspth]

What's the use case? This is generally what the flag type is meant to support, so the boolean aspect is whether or not the key has a value in Redis.

[MrHubble]

I didn't realise that flag was meant for this use case.

I'm happy to close this PR if it adds no value.

Thanks for the feedback. I'm a big fan of your work.

[azyzio]

Hi,

Thanks for this great encapsulation :) Had to build a custom framework for this kind of things before.

I can actually see a use case for booleans with defaults:

• we can have several user settings to enable / disable certain features, e.g. reports_enabled, api_enabled, notifications_enabled
• For consistency, we want to keep all naming to have _enabled suffix
• By default, we want to keep certain features enabled and others disabled

Right now, we could do it by raising flags in an after_craete callback, but a default option would be nicer.

Also, flags seem to be great for 'flagging' things. E.g. crossed_the_finish_line, invitation_sent. It feels that settings like above are a kind of different category. But this is a minot thing :)

Maybe you can see a better place for settings like those?

Best,
Adam