Update app.py

app.py

@@ -68,6 +68,9 @@ if st.button('Run the ad campaign and display the results'):
 
         for epoch in range(epochs):
 
+            # The neural network is used to choose the action
+            # To display the learning progress, we also record the 
+            # model output, loss and gradients
             output, action, loss, grads = action_selection(model)
 
             # Next we are applying the action by displaying ad A or B