As all Open Source software, contributions to Sugarizer are welcome.
The best way to start is to read the architecture then to do the whole tutorial. It will give you a good understanding of Sugarizer internal.
Then, you could start to contribute by trying to fix some existing issues here.
Note than the master branch of the repository is for released/stable version, the dev branch is for development. So to contribute:
Please note there is no need to ask permission to work on an issue. You should check for pull requests linked to an issue you are addressing; if there are none, then assume nobody has done anything. Begin to fix the problem, test, make your commits, push your commits, then make a pull request. Mention an issue number in the pull request, but not the commit message. These practices allow the competition of ideas and give priority to meritocracy.
Thanks in advance for your contribution.