Contributions are managed most easily via pull requests. This project is hosted at https://github.com/comcast/weasel . Head over, fork the project and open a pull request.
Weasel is not designed as a general-purpose all-encompasing license checker. Those exist, but are more difficult to use and configure. Weasel is designed specifically for projects trying to meet Apache Software Foundation release guidelines.
Likewise, weasel considers false-positives to be better than
false-negatives. It's better to have a file incorrectly identified as
having a restrictive license (which you can then manually override) than
to have it incorrectly identified as having no license or a
non-restrictive license. Since many files may include no more license
information than a single Licensed GPL, weasel uses a very aggressive
approach.
Weasel expects that you'll prepare a directory for it and maintain it. It doesn't expect to run nicely on just any project. There are too many details to get right and attempting to make it work nicely without managing the un-automatable files will cause it to quietly miss potentially infringing licenses.
Weasel is designed to be run automatically, by Continuous Integration, as well as manually, by either commit-hook or fastidious human.
Weasel is intentionally devoid of dependencies. This makes it easy to pull and build on any possible system. It's possible that dependencies may provide significant value in the future, but their use should be weighed against the potential difficulty they may cause building the tool.