[gb] Option to auto-create and push existing content

For #85

gitblit/README.md

@@ -1,4 +1,4 @@
-Provides a ready-to-use instance of [GitBlit](http://gitblit.com/). 
+Provides a ready-to-use instance of [GitBlit](http://gitblit.com/).
 
 ## Basic usage
 
@@ -6,7 +6,7 @@ Start the GitBlit container using
 
     docker run -d -p 80:80 -p 443:443 --name gitblit itzg/gitblit
 
-Access its web interface at the mapped HTTP (80) or HTTPS (443) port of the 
+Access its web interface at the mapped HTTP (80) or HTTPS (443) port of the
 Docker host. Login with the default credentials __admin__ / __admin__ .
 
 
@@ -18,14 +18,21 @@ In order to allow for future upgrades, run the container with a volume mount of
 
 ## Initial repository creation
 
-As a convenience for cluster configuration management with git 
-(such as with [Spring Cloud Config](https://cloud.spring.io/spring-cloud-config/)), 
+As a convenience for cluster configuration management with git
+(such as with [Spring Cloud Config](https://cloud.spring.io/spring-cloud-config/)),
 you may specify the name of an initial repository to be owned by the 'admin' user.
 This can be enabled by passing the name of that repository via the environment
 variable `GITBLIT_INITIAL_REPO`, such as
 
     -e GITBLIT_INITIAL_REPO=default
 
+## Create repositories with content
+
+In addition to the approach above, you can push repostories with existing
+content by attaching them to sub-directories of `/repos`, such as
+
+    docker run -v $HOME/git/example:/repos/example ...
+
 ## Custom configuration
 
 You can add or override any of the `*.properties` files for configuring GitBlit,
@@ -34,6 +41,6 @@ typically `gitblit.properties`, by placing those files in a volume attached at
 
     -v $(pwd)/extra-config:/config
 
-The property files in that configuration directory will be renamed with the 
+The property files in that configuration directory will be renamed with the
 suffix `.applied` to avoid overwriting manually modified configuration on
 the next container startup.