Add option for project-specific context files

General idea

I would love to see a feature similar to what Robitx/gp.nvim#50 has with their :GpContext command, namely being able to add a file like .chatgpt.md to the git root directory, the content of which would then be prepended to new chats - either as a system message, or actually prepended to the first user message.

Usecase

I find myself re-typing the same context quite often, e.g.:

I am working on a django project. I have models A, B, and C. B has a foreign key to C. I also have a modelform AForm, BForm, CForm for each of those models. 

before getting to my actual question.

Another usecase would be something like:

Only use python, typescript, tailwind CSS, and django templates (depending on what is necessary) to accomplish the following task:

Obviously this context is highly project dependant, but it is also very much a constant within each project.

Proposed solution

Add two new options, e.g. project_context_file and project_context_type. If the project_context_file exists in the git root, set its content as the system message if project_context_type == "system" or prepend it to the first message of each new chat if project_context_type == "prepend" (or something along those lines).