group, ungroup: New commands to indicate groups of repositories.

doc/git-annex.mdwn

@@ -248,6 +248,15 @@ subdirectories).
   Indicates that the repository has been irretrevably lost.
   (To undo, use semitrust.)
 
+* group repository groupname
+
+  Adds a repository to a group, such as "archival", "enduser", or "transfer".
+  The groupname must be a single word.
+
+* ungroup repository groupname
+
+  Removes a repository from a group.
+
 # REPOSITORY MAINTENANCE COMMANDS
 
 * fsck [path ...]

doc/internals.mdwn

@@ -67,6 +67,14 @@ Example:
 
 Repositories not listed are semi-trusted.
 
+## `group.log`
+
+Used to group repositories together.
+
+The file format is one line per repository, with the uuid followed by a space,
+and then a space-separated list of groups this repository is part of,
+and finally a timestamp.
+
 ## `aaa/bbb/*.log`
 
 These log files record [[location_tracking]] information