README: add details section.

README.md

@@ -13,6 +13,15 @@ Usage
 This will create a git repository in `gitdir/`, containing the whole history of
 the dokuwiki pages, one commit per change.
 
+Details
+-------
+
+Change files (`*.changes`) under `data/meta` are read for changelog information
+of each page. The changelog of all pages is then sorted by date, and a separate
+commit is created from each changelog entry, with the content taken from
+`data/attic/<pagename>.<timestamp>.txt.gz`. The original *author name*, *IP*,
+*date* and *change message* become standard parts of the created git commit.
+
 License
 -------
 
@@ -21,4 +30,4 @@ dokuwiki2git is licensed under AGPLv3.
 Contacting
 ----------
 
-Bugs? Feature requests? Mail the author
+Bugs? Feature requests? Mail the author!