added symbolical index.html file

github's hello world guide
Revert "added symbolical index.html file"

This reverts commit 811761cedcfa50fb737f3440bc96a2958ad21035.
Revert "Revert "added symbolical index.html file""

This reverts commit 1c1c917ed80a3c58b5aab866e9dd971b3d57caaa.