Set PYTHONPATH environment variable (#173)

This is necessary for running tools in this repository.

Author: petrhosek

Dockerfile

@@ -6,5 +6,5 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
     && rm -rf /var/lib/apt/lists/*
 COPY . /ml-compiler-opt
 RUN python3 -m pip install -r /ml-compiler-opt/requirements.txt
+ENV PYTHONPATH=/ml-compiler-opt
 VOLUME /external
-