fix permission issue between new pipenv, its cache, and celery; also pin pipenv

Dockerfile

@@ -1,21 +1,20 @@
 FROM python:3.6-slim
 RUN apt-get update && apt-get install -y supervisor redis-server
-RUN pip install pipenv
+RUN pip install pipenv==2018.10.13
 
 ENV WORKON_HOME=/venv
+ENV C_FORCE_ROOT="true"
 
 WORKDIR /app
 
 ADD Pipfile /app
 ADD Pipfile.lock /app
 
-RUN pipenv install --verbose
+RUN pipenv install
 
 ADD . /app
 
 EXPOSE 5000
 
-ENV C_FORCE_ROOT=1
-
 
 CMD /usr/bin/supervisord

supervisord.conf

@@ -20,7 +20,7 @@ stdout_logfile=/dev/stdout
 stdout_logfile_maxbytes=0
 stderr_logfile=/dev/stdout
 stderr_logfile_maxbytes=0
-user=nobody
+user=root
 command=bash -c "scripts/run_celery.sh"
 
 [program:celery-beat]