Documentation for "forbidden" document field names

[cstamas]

AFAIK Documents might not have fields named as "id".

It got unnoticed by KZ all way until indexes were added (documents with field named "id" does work with KZ just fine, until you try to index them), as the index creation process was the only one point that threw an exception. And later, by mailing with Sunny, revealed to me that fields named as "id" is no-no.

[sunnygleason]

I will definitely do this!