Update index.html

I'm one of your fans and the index.html is the part that has all the important info for a website to run, I copied this from one of your videos by pausing. I fixed some things so that it's easier to follow on from Part 4 of the Jekyll Tutorial Series thing
This is for enabling an "Add to homescreen" kind of situation in safari. Not really a common use case, unless you are making a web app.