We believe that the most effective way to manage a product like this is to ensure that there is minimum repetition of code. So before contributing a function, please make sure that such a feature or function does not exist else where. If it does, the try and extend that function to accommodate your use case.
DocTypes are easy to create but hard to maintain. If you find that there is a another DocType with a similar functionality, then please try and extend that functionality. For example, by adding a "type" field to classify the new type of record.
Tabs!
The ERPNext code is licensed as GNU General Public License (v3) and the Documentation is licensed as Creative Commons (CC-BY-SA-3.0) and the copyright is owned by Web Notes Technologies Pvt Ltd (Web Notes). Unless otherwise asserted in the code files, Web Notes will own the copyright of all contributions too. That means Web Notes holds the rights to change the license in the future or offer Commercial Licenses.
We will only accept copyright assertions in case of a significant contribution like a whole new functionality or a major rewrite. We believe if your contribution is significant then you should have a say in what license Web Notes selects in the future and/or have a right to any revenue Web Notes gets from a Commercial License. Either ways Web Notes will have the right to decide what is a "significant" contribution.
Note: At the moment, Web Notes does not give Commercial License for ERPNext nor has specific plans do so in the future.
The brand name ERPNext and the logo are trademarks of Web Notes Technologies Pvt. Ltd.