add discussion on transfer learning

[erinmgraham]

Ep 06 add discussion on transfer learning and/or give practical examples of where to go to find out how more

[erinmgraham]

Andrew: On transfer learning: there are pretrained models such as ResNet that can be used to for generic classification problems. The pretrained parts of the model can be thought of as being trained to find properties / patterns in images, which then are combined to make new predictions based on these pretrained feature detectors. This would overcome some of the concerns about transfer learning that were raised