Add a basic tutorial for the tools in depot_tools.

docs/man1/git-rebase-update.1

 '\" t
 .\"     Title: git-rebase-update
 .\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
 .\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
-.\"      Date: 03/25/2014
+.\"      Date: 04/10/2014
 .\"    Manual: Chromium depot_tools Manual
-.\"    Source: depot_tools 207bff1
+.\"    Source: depot_tools 68b1017
 .\"  Language: English
 .\"
-.TH "GIT\-REBASE\-UPDATE" "1" "03/25/2014" "depot_tools 207bff1" "Chromium depot_tools Manual"
+.TH "GIT\-REBASE\-UPDATE" "1" "04/10/2014" "depot_tools 68b1017" "Chromium depot_tools Manual"
 .\" -----------------------------------------------------------------
 .\" * Define some portability stuff
 .\" -----------------------------------------------------------------
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 .\" http://bugs.debian.org/507673
 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
 .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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 .fi
 .if n \{\
 .RE
 .\}
 .sp
 .SH "SEE ALSO"
 .sp
 \fBgit-new-branch\fR(1), \fBgit-reparent-branch\fR(1), \fBgit-rename-branch\fR(1), \fBgit-upstream-diff\fR(1), \fBgit-freeze\fR(1), \fBgit-mark-merge-base\fR(1)
 .SH "CHROMIUM DEPOT_TOOLS"
 .sp
-Part of the chromium \fBdepot_tools\fR(1) suite\&. These tools are meant to assist with the development of chromium and related projects\&. Download the tools from \m[blue]\fBhere\fR\m[]\&\s-2\u[1]\d\s+2\&.
+Part of the chromium \fBdepot_tools\fR(7) suite\&. These tools are meant to assist with the development of chromium and related projects\&. Download the tools from \m[blue]\fBhere\fR\m[]\&\s-2\u[1]\d\s+2\&.
 .SH "NOTES"
 .IP " 1." 4
 here
 .RS 4
 \%https://chromium.googlesource.com/chromium/tools/depot_tools.git
 .RE