Is it possible to submit new code/features?

Hello,
I'm not sure about how to do that, so I create an issue.

For a own project I added features to jammer generic, and would like to know if it is possible (and how) to submit these changes into to main code.

Here are the feaures:
- possibility to choose for 'disabling' (read-only field) fields rather than hide them
- possibility to add an exception to not hide/disable when creating content (only applies when modifying existing content)
- possibility to restrict action by user roles
I also added the possibility to modify existing entries, and tuning some minor stuff (i.e. message that indicate that data were not saved is 'message' rather than 'error').

Regards.