The source code to Amara is available on Github. Feel free to fork the project and open a pull request.
Before working on a sizeable feature, please do run it by us in our IRC channel. We don’t want you to waste your time working on something we don’t really want. We are at #amara on freenode.
Amara is freely available under the terms of the GNU Affero General Public License. You can find the full text of the license here.