The whole "The Russians Hacked the DNC!" affair was cooked up by the Hillary campaign in concert with Trump's enemies in the intelligence community as a way for the media and the Democrats to distract the public from the embarrassing WikiLeaks e-mail disclosures during Hillary's election campaign of the DNC colluding with the media, their trashing of Bernie Sanders, etc.
There are were two actual leaks. The first happened when Hillary's campaign manager, John Podesta, responded to a 'change your password' phish email. He clicked on it and gave away his password. It was a trick that could have been done by a 14 year old. Podesta used the same password for his gmail, Twitter, Facebook, etc. No skills involved, anybody could have done it, and there is no evidence of elite 'Russian hackers' using sophisticated or deep techniques to infiltrate his laptop. Podesta was just an idiot.
Second, all of the alleged evidence of "Russian fingerprints" on the so-called hacked DNC servers comes from just one guy: Dmitry Alperovitch, the Russian ex-pat head of the shady security firm CrowdStrike, whom the DNC had paid to check their servers.
There is a flattering article on Dmitry in Esquire where Dmitry brags about how he 'discovered the Russian hackers' using his fancy counterhacker tools (basically a free advertisement for CrowdStrike). See http://www.esquire.com/news-politics/a49902/the-russian-emigre-leading-the-fight-to-protect-america/ .
Keep in mind that:
Basically Dmitry was paid by the DNC to find what they wanted him to find, and he did.