added food scaling from land function

[OttaviaTr]

Added food scaling from land function #101

[jucordero]

Hi @OttaviaTr! This looks good.
I'll add a few comments and suggestions below, but the core of the function seems exactly like what we had in mind

[jucordero]

While we don't enforce it too strictly, we try to limit line length to 79 characters or less (See PEP8)

Other projects are even more strict and block merging if a PEP8 style test is not passed.

In this case only docstrings seem to be above the limit, so it is just a matter of adding line breaks to the longer parameter descriptions

[jucordero]

Hi @OttaviaTr, It all looks good to me.
Please merge this by clicking in "Squash and merge"
This will convert all your commits into a single commit that will merge into the ffc_model branch.

If at any point we need to make amendments or add more functionality to these functions, we will need a new branch in your fork and a new PR.