Development.md

@@ -3,6 +3,7 @@ This page can be used by developers to better understand certain parts of the co
 - [Vertical Interpolation](#vertical-interpolation)
 - [Write Grib2 files](#write-grib2-files)
 - [Install and update NES inside Conda environment](#install-and-update-nes-inside-conda-environment)
+- [Upload to PyPI](#upload-to-pypi)
 
 ## Vertical interpolation
 
@@ -117,4 +118,39 @@ This will install the current version of NES that is in the machine. If NES is u
 1. Update the NES version in the machine used for the Conda environment, e.g. deploy the NES code there.
 2. Repeat the steps above for the installation.
 
-You can also check the complete [NES source code](https://earth.bsc.es/gitlab/es/NES/-/blob/master/nes/nc_projections/default_nes.py#L2977)
+You can also check the complete [NES source code](https://earth.bsc.es/gitlab/es/NES/-/blob/master/nes/nc_projections/default_nes.py#L2977)
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+
+## Upload to PyPI
+
+Every time a version is released, we should update [NES in PyPI](https://pypi.org/project/NES/). To do so, we will first create a source distribution:
+
+```
+python setup.py sdist
+```
+
+We can check if it can be installed doing:
+```
+pip install dist/NES-1.X.X.tar.gz
+```
+
+If everything is correct, we can proceed to upload our distribution to the website. For this we need to install twine:
+
+```
+pip install twine
+```
+
+And get an API key in PyPI. I recommend creating a folder in your home directory called .pypirc, with the following content:
+
+```
+[pypi]
+  username = __token__
+  password = pypi-[key]
+```
+
+That way you won't be asked for the your credentials anymore. Make sure the version name has been updated in __init__.py, and no more changes are needed since **it is not allowed to update the repository for that version once it is uploaded even if deleted**.
+
+To upload it, you can do:
+
+```
+twine upload dist/NES-1.X.X.tar.gz
+```
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