Enable to use GPU for teklia_dan_predict

Closes #119 (closed)

dan/predict/__init__.py

@@ -148,4 +148,10 @@ def add_predict_parser(subcommands) -> None:
         type=int,
         default=0,
     )
+    parser.add_argument(
+        "--gpu-device",
+        help="Use a specific GPU if available.",
+        type=int,
+        required=False,
+    )
     parser.set_defaults(func=run)