Document how to use pyposeidon with an existing schism model that has not been generated by pyposeidon

[pmav99]

This is how it's done:

import pyposeidon

params = {
    "solver_name": "schism",
    "rpath": "/path/to/model/directory/",
}

model = pyposeidon.model.set(**params)
model.results()

The question is where in the docs, should we put this

[brey]

@pmav99 It is already there at the bottom of https://pyposeidon.readthedocs.io/en/latest/model.html.

We can add your snippet above there.

Noted for the docs update.

[pmav99]

If memory serves, the call to .results() is kind of mandatory and it is not mentioned in the docs. Or at least, after skimming through the docs, it was not apparent to me that I should call it.

That's why I opened the ticket.