At some point in the project, we have to move code from the development environment to the staging and ultimately the production environment. There are a number of ways of doing this.
Firstly, you need to identify what it is that you are moving across. Given that eZ publish should already be installed on the staging and production environments, you only need to upload the elements that you have changed.
This approach works fine until content population commences. Ideally, all development would happen before content population commences but sometimes, due to time constraints, content population starts before development is completed. This can work if handled carefully. What you need to do is ensure that all the content classes have been defined and permissions relating to users and groups are complete. At this point, you should be able to release this to staging for content to be entered. You can then continue developing features that will then use that content...