Beside the comments in the code itself, I also wrote an article which you can find here with further explanations on ResNet.
resnet.py: Implementation of the resnet architecture.residual.py: Implementation of a single residual block.ResNet Train.ipynb: Notebook to train the implementation of ResNet.layers: Contains files implementing basic layers [convolutions, max pooling and fully connected].
If you are having trouble viewing the notebook file, click here