Update README.md

README.md

@@ -45,6 +45,7 @@ Each CSV file contains experimental results with the following columns:
 | `dataset` | Name of the RDB dataset used (e.g., "rel-avito", "rel-f1") |
 | `task` | Name of the prediction task (e.g., "ad-ctr", "user-clicks") |
 | `seed` | Random seed for reproducibility |
+| `gnn`  | Type of Graph Neural Network (GNN) (e.g., "GraphSAGE", "GIN", "GPS")
 
 ### Graph Column Specification