Add style transfer demo to index

Author: smessmer

README.md

@@ -20,6 +20,7 @@
 * [Transferring SqueezeNet from PyTorch to Caffe2 and to Android app](tutorials/PytorchCaffe2MobileSqueezeNet.ipynb)
 * [Serving PyTorch Models on AWS Lambda with Caffe2 & ONNX](https://machinelearnings.co/serving-pytorch-models-on-aws-lambda-with-caffe2-onnx-7b096806cfac)
 * [Serving ONNX models with MXNet Model Server](tutorials/ONNXMXNetServer.ipynb)
+* [Converting Style Transfer model from PyTorch to CoreML and deploying to an iPhone](https://github.com/onnx/tutorials/tree/master/examples/CoreML/ONNXLive)
 
 ## ONNX tools