docs: added restore archived repository documentation

docs/admin/restore-deleted-repositories.rst

@@ -0,0 +1,42 b''
+.. _restore-deleted-repositories:
+
+Restoring Deleted Repositories
+==============================
+
+By default when repository or whole repository group is deleted an archived copy
+of filesystem repositories are kept. You can see them as special entries in the
+repository storage such as::
+
+    drwxrwxr-x   3 rcdev rcdev  4096 Dec  4  2017 rm__20171204_105727_400795__ce-import
+    drwxrwxr-x   6 rcdev rcdev  4096 Nov 21  2017 rm__20180221_152430_675047__svn-repo
+    drwxr-xr-x   7 rcdev rcdev  4096 Mar 28  2018 rm__20180328_143124_617576__test-git
+    drwxr-xr-x   7 rcdev rcdev  4096 Mar 28  2018 rm__20180328_144954_317729__test-git-install-hooks
+
+
+Data from those repositories can be restored by simply removing the
+`rm_YYYYDDMM_HHMMSS_DDDDDD__` prefix and additionally only in case of Mercurial
+repositories remove the `.hg` store prefix.::
+
+    rm__.hg => .hg
+
+
+For Git or SVN repositories this operation is not required.
+
+After removing the prefix repository can be brought by opening
+:menuselection:`Admin --> Settings --> Remap and Rescan` and running `Rescan Filesystem`
+
+This will create a new DB entry restoring the data previously removed.
+To restore OLD database entries this should be done by restoring from a Database backup.
+
+RhodeCode also keeps the repository group structure, this is marked by entries that
+in addition have GROUP in the prefix, eg::
+
+    drwxr-xr-x   2 rcdev rcdev  4096 Jan 18 16:13 rm__20181130_120650_977082_GROUP_Test1
+    drwxr-xr-x   2 rcdev rcdev  4096 Jan 18 16:13 rm__20181130_120659_922952_GROUP_Docs
+
+
+
+.. note::
+
+    RhodeCode Tools have a special cleanup tool for the archived repositories. Please
+    see :ref:`clean-up-cmds`

docs/admin/system-admin.rst

@@ -30,3 +30,5 b' The following are the most common system'
     enable-debug
     admin-tricks
     cleanup-cmds
+    restore-deleted-repositories
+