add GCN implementation

gcn/README.md

@@ -0,0 +1,17 @@
+# Graph Convolutional Network
+
+An example of [GCN](https://arxiv.org/pdf/1609.02907.pdf%EF%BC%89) implementation with MLX.
+
+### Install requirements
+First, install the few dependencies with `pip`.
+
+```
+pip install -r requirements.txt
+```
+
+### Run
+To try the model, just run the `main.py` file. This will download the Cora dataset, run the training and testing.
+
+```
+python main.py
+```