Add user/group management docs to werc site.

sites/werc.cat-v.org/docs/user_management.md

@@ -0,0 +1,31 @@
+User and Group Management
+=========================
+
+User accounts and group membership are stored under `etc/users/` and `etc/groups/` respectively.
+
+A user account consists of a directory under `etc/users/` that contains files with that users account information, the only required file is `password` containing a password for the user. For example:
+
+	% ls etc/users/
+	eekee  uriel  yosyp
+	% cat etc/users/uriel/password
+	mypass
+
+Groups consists of files named after the group name stored in `etc/groups/`, containing the names of the group members, one per line.
+
+The group 'admin' is 'built-in' and any members in that group will have admin privileges for most werc apps by default.
+
+Example
+-------
+
+To create a user called [glenda](http://glenda.cat-v.org) that is a member of the group `rabbits` you can do:
+
+	% mkdir etc/users/glenda/
+	% echo passw > etc/user/glenda/password
+	% echo glenda >> etc/users/rabbits
+
+Utils
+-----
+
+The script at bin/aux/addwuser.rc allows you to even more trivially add users. 
+
+	addwuser.rc user_name user_pass [groups ...]