http-backend: add example for gitweb on same URL

In the git-http-backend documentation, add an example of how to set up
gitweb and git-http-backend on the same URL by using a series of
mod_alias commands.

Signed-off-by: Mark Lodato <lodatom@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-http-backend.txt

@@ -88,6 +88,23 @@ directive around the repository, or one of its parent directories:
 	...
 </Location>
 ----------------------------------------------------------------
++
+To serve gitweb at the same url, use a ScriptAliasMatch to only
+those URLs that 'git-http-backend' can handle, and forward the
+rest to gitweb:
++
+----------------------------------------------------------------
+ScriptAliasMatch \
+	"(?x)^/git/(.*/(HEAD | \
+			info/refs | \
+			objects/(info/[^/]+ | \
+				 [0-9a-f]{2}/[0-9a-f]{38} | \
+				 pack/pack-[0-9a-f]{40}\.(pack|idx)) | \
+			git-(upload|receive)-pack))$" \
+	/usr/libexec/git-core/git-http-backend/$1
+
+ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/
+----------------------------------------------------------------
 
 Accelerated static Apache 2.x::
 	Similar to the above, but Apache can be used to return static
@@ -102,6 +119,22 @@ AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$          /var/www/git/$1
 AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1
 ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/
 ----------------------------------------------------------------
++
+This can be combined with the gitweb configuration:
++
+----------------------------------------------------------------
+SetEnv GIT_PROJECT_ROOT /var/www/git
+
+AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$          /var/www/git/$1
+AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1
+ScriptAliasMatch \
+	"(?x)^/git/(.*/(HEAD | \
+			info/refs | \
+			objects/info/[^/]+ | \
+			git-(upload|receive)-pack))$" \
+	/usr/libexec/git-core/git-http-backend/$1
+ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/
+----------------------------------------------------------------
 
 
 ENVIRONMENT