The temperature about this is getting high.  Some Trump supporters claim it's a desperate gasp by the Dems to overturn results, but I haven't come across any serious claims that voting machines were affected, other than a mention of it by Jill Stein.  And it also isn't a sudden fabrication by the White House;there was  talk of it in October, and Trump, albeit perhaps jokingly, egging the Russians on.  Even though it probably was a joke, it should remind us that this is not a sudden break.
Put your hand up if you trust Putin.  I thought so!  Now put your hand up if you trust the CIA.  Hey -- about the same result!  But we should note that the Brits & Germans are quite concerned, and it's a stretch to think they're in the pockets of the DNC along with the CIA.  A little while ago, people clained the intelligence community liked Trump and hated Clinton/Obama -- remember James Comey?  
Investigate and publish.  Trump says it's ridiculous? He also says there were millions of illegal votes.