Index file for ddoc

[tcak via Digitalmars-d-learn]

Maybe I am missing, but I do not see any index file when html 
files are generated by ddoc. Is there any way to generate index 
file automatically, so, a tree like links will be listed all 
created documentation files?

If the problem is about the possibility of having index.d and it 
would be confused with index.html, I can understand.