Add the feature names to the classifier object

That way, if we load it, we can already retrieve what the names of
features were for.

train_model.py

@@ -367,6 +367,9 @@ if __name__ == "__main__":
     classifier = RandomForestClassifier()
 
     classifier.fit(X_train, y_train, w_train)
+    # We just add it to the class
+    classifier.feature_names = poly_transformer.get_feature_names()
+
     print("Accuracy: {0}".format(classifier.score(X_test, y_test, w_test)))
     print("Classifier trained")