As a word of caution: I'm a data scientist, not a web developer or a developer at all. But sometimes one finds itself in a position, where it's necessary to write a web application. This happened to me recently when I had to write a small Django web app that manages and documents A/B tests.

One of the features of this app is an automated test evaluation. And what do you need for an evaluation? Data! And how do you get data? By uploading a file.