webapp which hosts rubygems or a proxy to rubygems. delivers gem maven artifacts as well. the proxy can be configured to be caching proxy or non-caching proxy
the regular webapp with hosted and (caching-)proxy can be built with
 mvn package
or just run it in place with
 mvn jetty:run
where the hosted rubygems are located under http://localhost:8989/hosted and the proxy with https://rubygems.org as source is reachable under http://localhost:8989/caching or http://localhost:8989/proxy. and the http://localhost:8989/merge will combine all three to on rubygems repository.
you also can start the war like this (using embedded jetty):
 mvn package -Pexecutable
 java -jar target/rubygems.war
and adjust the <rubygems.properties> to your liking.
add them to your gem command
gem sources add <http://localhost:8989/hosted>gem sources add <http://localhost:8989/caching>gem sources add <http://localhost:8989/proxy>gem sources add <http://localhost:8989/merged>
or use the (caching-)proxy with bundler (example only for https://rubygems.org)
bundler config mirror.https://rubygems.org http://localhost:8989/proxybundler config mirror.https://rubygems.org http://localhost:8989/cachingbundler config mirror.https://rubygems.org http://localhost:8989/merged
the Gem-Artifacts are accessible via
- http://localhost:8989/hosted/maven/releases
 - http://localhost:8989/hosted/maven/prereleases
 - http://localhost:8989/caching/maven/releases
 - http://localhost:8989/caching/maven/prereleases
 - http://localhost:8989/proxy/maven/releases
 - http://localhost:8989/proxy/maven/prereleases
 - http://localhost:8989/merged/maven/releases
 - http://localhost:8989/merged/maven/prereleases
 
you need a mirror declaration http://rubygems-proxy.torquebox.org/releases and http://rubygems-proxy.torquebox.org/prereleases in your settings.xml
<settings>
  <mirrors>
    <mirror>
      <id>gems</id>
      <name>Rubygems</name>
      <url>http://localhost:8989/caching/maven/releases</url>
      <mirrorOf>rubygems-releases</mirrorOf>
    </mirror>
    <mirror>
      <id>pregems</id>
      <name>Rubygems Prereleases</name>
      <url>http://localhost:8989/caching/maven/prereleases</url>
      <mirrorOf>rubygems-prereleases</mirrorOf>
    </mirror>
since some old gem-artifacts use the those repositories (old in sense they originally came from rubygems-proxy.torquebox.org)
for more details about Gem-Artifacts see https://github.com/sonatype/nexus-ruby-support/wiki/Gem-Artifacts. for a solution with access control, more advanced proxy features and merging (group) to repositories see https://github.com/sonatype/nexus-ruby-support.
the underlying library nexus-ruby-tools can handle gem push my-1.0.0.gem but somehow I have not deciphered how to use rubygems.org and a local repo without manually editing the config files.
the easiest way is to use the nexus gem which was tailor made for the nexus-ruby-tools.
gem install nexus
``
then you can upload your gem with
gem nexus my-1.0.0.gem
it will prompt for the url which is http://localhost:8989/hosted from above. empty username and password will finally push the gem. since the username and passoword was empty it will be prompted again.
non-caching proxy
---
this proxy configuration does not cache the gem-files itself but instead sends a redirect to <rubygems.org>. all other files are cached the same way as the caching proxy:
    mvn jetty:run -P proxy
with url <http://localhost:8989/proxy>
rubygems-proxy.torquebox.org (not yet installed)
--
the webapp for this rubygems-proxy is under the profile **legacy**
     mvn clean package -Plegacy
which is just a proxy (mvn jetty:run -Plegacy)
*  <http://localhost:8989/releases>
*  <http://localhost:8989/prereleases>
tests
====
some integration tests for proxy feature can be executed with
    mvn -P run-its
	
    mvn -P run-its -Plegacy
deploy to maven central
-----------------------
    mvn versions:set
    git ci -m 'prepare release' pom.xml
    mvn -Prelease,executable
    git tag ...
    mvn versions:set
    git ci -m 'next dev version' pom.xml
    git push
    git push --tags
contributing
------------
1. Fork it
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Added some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create new Pull Request
meta-fu
-------
enjoy :) 
