Mr. Sanders was a candidate for the Democratic nomination for the Presidency.  That is different from being a candidate for president.  Ms. Clinton defeated Mr. Sanders and was nominated by the Democratic Party to be the Candidate for Presidency in November, 2016.  Her name will be on the ballot, Senator Sanders' will not.  

Additionally, you statement re: Sanders' voters is simply untrue:  Here's a July 16, Pew survey: 

"Support for Clinton is slightly higher among Democrats and Democratic leaners who backed Sanders in the primary contests: 85% say they plan to vote for Clinton in the general election, compared with 9% who say they will vote for Trump and 6% who volunteer that they will vote for another candidate or don’t know."  

You can easily access other surveys and polls which support the 85 to 90% figure.  Certainly, Trump supporters WISH it were otherwise...but it isn't.  

I don't expect you will correct your error, but I did want to point it out to you.  regards, Gary