For anyone else looking, this is what we're doing now.

```
  <repositories>
    <repository>
      <id>mavengems</id>
      <url>mavengem:https://rubygems.org</url>
    </repository>
  </repositories>

  <pluginRepositories>
    <pluginRepository>
      <id>mavengems</id>
      <url>mavengem:https://rubygems.org</url>
    </pluginRepository>
  </pluginRepositories>

  <build>
    <extensions>
      <extension>
        <groupId>org.torquebox.mojo</groupId>
        <artifactId>mavengem-wagon</artifactId>
        <version>0.2.0</version>
      </extension>
    </extensions>
```