Documentation/gitpacking.txt: initial commit

Introduce a new manual page, gitpacking(7) to collect useful information
about advanced packing concepts in Git.

In future commits in this series, this manual page will expand to
describe the new pseudo-merge bitmaps feature, as well as include
examples, relevant configuration bits, use-cases, and so on.

Outside of this series, this manual page may absorb similar pieces from
other parts of Git's documentation about packing.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/Makefile

@@ -51,6 +51,7 @@ MAN7_TXT += gitdiffcore.txt
 MAN7_TXT += giteveryday.txt
 MAN7_TXT += gitfaq.txt
 MAN7_TXT += gitglossary.txt
+MAN7_TXT += gitpacking.txt
 MAN7_TXT += gitnamespaces.txt
 MAN7_TXT += gitremote-helpers.txt
 MAN7_TXT += gitrevisions.txt

Documentation/gitpacking.txt

@@ -0,0 +1,34 @@
+gitpacking(7)
+=============
+
+NAME
+----
+gitpacking - Advanced concepts related to packing in Git
+
+SYNOPSIS
+--------
+gitpacking
+
+DESCRIPTION
+-----------
+
+This document aims to describe some advanced concepts related to packing
+in Git.
+
+Many concepts are currently described scattered between manual pages of
+various Git commands, including linkgit:git-pack-objects[1],
+linkgit:git-repack[1], and others, as well as linkgit:gitformat-pack[5],
+and parts of the `Documentation/technical` tree.
+
+There are many aspects of packing in Git that are not covered in this
+document that instead live in the aforementioned areas. Over time, those
+scattered bits may coalesce into this document.
+
+SEE ALSO
+--------
+linkgit:git-pack-objects[1]
+linkgit:git-repack[1]
+
+GIT
+---
+Part of the linkgit:git[1] suite