- adding function to prepopulate database with
- moving `/exercise/` endpoint to `/media/` endpoint
- instead of using the authentiaction as a global dependency, it is used with
  the protected endpoints directly
- adding progress endpoint
- adding workout endpoint
- changing users endpoint

- sklearn.discriminant_analysis.LinearDiscriminantAnalysis
- sklearn.linear_model.SGDClassifier
- sklearn.neighbors.KNeighborsClassifier
- sklearn.neural_network.MLPClassifier
- sklearn.svm.LinearSVC
- sklearn.svm.SVC
- sklearn.tree.DecisionTreeClassifier

THIS IS A BREAKING CHANGE!

The old history is backed up locally in case it is needed later on.