Update clockwork

[knoxknox]

Update link and description for gem 'clockwork'.
Looks like this gem is not maintained by original authors.

[markets]

hi @knoxknox, but the original source points out:

This fork is no longer maintained, maybe try this one: https://github.com/Rykian/clockwork

But, in this fork I also found this: Rykian/clockwork#1.

So I'm not sure if this is really an option right now, if we take into account "competitors" like whenever, rufus-scheduler... Keep a link to a 404 isn't really good.

[knoxknox]

Hi @markets, yes I saw this, but this is one of the authors of this gem.

What is your suggestion ?
Also I'm not sure about rubygems. Looks like version in rubygems also is not maintained.

[markets]

Yes, there is actually some uncertainty... I also found this thread on Reddit: https://m.reddit.com/r/rails/comments/5a68on/what_happened_to_the_clockwork_gem

So, probably right now best movement is to remove it from the list (we can add it back in case the project "revives" again). Btw, zhong seems a good lib for a distributed solution: https://github.com/nickelser/zhong (#657)

[knoxknox]

@markets done, gem was removed from list

[markets]

Thanks @knoxknox, this is a proper move IMHO!

There is also a discussion here, in the original repo: adamwiggins/clockwork#23