I sent a few emails, and it sounds like you can format your GitHub repository like a measure-gem manually and that is sufficient for having a repository that can be added to the BCL. Here's an example of what that layout would look like for a general repository of measures if anyone else has a similar question:

openstudio-measure-repo/  
├── README.md  
├── LICENSE  
└── lib/  
    └── measures/  
        ├── measure1/  
        │   ├── measure.rb  
        │   ├── measure.xml  
        │   ├── resources/  
        │   │   └── helper.rb  
        │   └── test/  
        │       └── measure1_test.rb  
        └── measure2/  
            ├── measure.rb  
            ├── measure.xml  
            ├── resources/  
            │   └── helper.rb  
            └── test/  
                └── measure2_test.rb