issue 62 fix (#63)

Adding the HOME variable makes the Docker build process create and use the /httpbin/.local folder in both build and runtime. Without this, the Dockerfile creates a folder /root/.local and uses it while the specified user is root. However, in the case of a user override with runAsUser or a similar command, /root is no longer the home directory and is not accessible to the non-root user. This line fixes this issue. It has been fixed and tested locally.

Dockerfile

@@ -5,10 +5,12 @@ LABEL description="A simple HTTP service."
 
 ENV LC_ALL=C.UTF-8
 ENV LANG=C.UTF-8
+ENV HOME=/httpbin
+
+WORKDIR /httpbin
 
 RUN apt update -y && apt install python3-pip libssl-dev libffi-dev git -y && pip3 install --no-cache-dir pipenv
 
-WORKDIR /httpbin
 ADD . .
 RUN pipenv sync