Give it couple of words you want to practice with and service will find sentences with them. You will need to guess the correct one.
Install and run:
pip install -r requirements.txt
TEXT_DB=./bases/german.sqlite FLASK_APP=exerciser/server.py flask run --host=0.0.0.0
Or with docker:
docker build -t der-trainer .
docker run -p 5000:5000 --rm -it der-trainer
And open http://localhost:5000/