recommendationservice: add requirements.txt

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

src/recommendationservice/compile_proto.sh

@@ -1,6 +1,6 @@
 # script to compile python protos
 #
 # requires gRPC tools:
-#   python -m pip install grpcio-tools googleapis-common-protos
+#   pip install -r requirements.txt
 
 python -m grpc_tools.protoc -I../../pb --python_out=. --grpc_python_out=. ../../pb/demo.proto

src/recommendationservice/requirements.txt

@@ -0,0 +1,2 @@
+grpcio-tools
+googleapis-common-protos