Add option to (re-)populate project from fixture

[ghost]

Research and add option to populate projects. This should affect only a specific project. Example:

When there are three projects A, B and C, I want to be able to reset the state of project B from a fixture (which can ben version-controlled in Git), without touching project A and / or B. On the other hand, I want to add a project called D from a fixture, without touching A, B, C.