[#71172128] change User#can_poke? method
[#71172128] change canpaigns#show to not show the poke form when user can't poke
[#71172128] add validation and change method name
[#71172128] remove Poke#any_recent_pokes?
[#71172128] add Poke.valid_frequency?
[#71172128] remove User#can_poke?
Merge pull request #43 from meurio/71172128

Add poke limitation of 24 hours between them