docs/usage: move Mercurial subrepository info to VCS support page

This commit moves the information verbatim, text changes will be done in a
subsequent commit.

docs/index.rst

@@ -32,7 +32,6 b' Administrators Guide'
    usage/locking
    usage/statistics
    usage/backup
-   usage/subrepos
    usage/debugging
    usage/troubleshooting
 

docs/usage/vcs_support.rst

@@ -44,6 +44,41 b' Also make sure to comment out the follow'
     use_threadpool =
 
 
+Mercurial support
+-----------------
+
+Working with Mercurial subrepositories
+``````````````````````````````````````
+Example usage of Subrepos with Kallithea::
+
+    ## init a simple repo
+    hg init repo1
+    cd repo1
+    echo "file1" > file1
+    hg add file1
+    hg ci --message "initial file 1"
+
+    #clone subrepo we want to add
+    hg clone http://kallithea.local/subrepo
+
+    ## use path like url to existing repo in Kallithea
+    echo "subrepo = http://kallithea.local/subrepo" > .hgsub
+
+    hg add .hgsub
+    hg ci --message "added remote subrepo"
+
+
+In the file list of a clone of ``repo1`` you will see a connected
+subrepo at the revision it was at during cloning. Clicking in
+subrepos link should send you to the proper repository in Kallithea.
+
+Cloning ``repo1`` will also clone the attached subrepository.
+
+Next we can edit the subrepo data, and push back to Kallithea. This will update
+both of the repositories.
+
+See http://mercurial.aragost.com/kick-start/en/subrepositories/ for more
+information about subrepositories.
 
 .. _waitress: http://pypi.python.org/pypi/waitress
 .. _gunicorn: http://pypi.python.org/pypi/gunicorn