Reorder of Dockerfile for painless configuration of envvars

Dockerfile

@@ -35,6 +35,12 @@ RUN curl -fSL -o pyenv-installer ${PYENV_INSTALLER_URL} &&\
     pyenv global ${PYTHON_VERSION} &&\
     pip install tornado pyzmq transitions
 
+USER root
+WORKDIR /data/
+COPY src/frontend /data/
+RUN yarn install --frozen-lockfile
+RUN yarn build --no-progress
+
 ENV TFW_WEB_PORT=4242
 ENV TFW_LOGIN_APP_PORT=6666
 ENV TFW_PUBLIC_PORT=8888
@@ -52,18 +58,12 @@ ENV TFW_SUPERVISORD_CONF="/etc/supervisor/supervisord.conf"
 
 ENV PYTHONPATH=${TFW_LIB_DIR}
 
-USER root
 COPY src/nginx /etc/nginx
 RUN chown -R ${AVATAO_USER}: /var/log/nginx /var/lib/nginx && \
     # nginx runs as a regular user, and can't write to /run
     sed -i 's#pid /run/nginx.pid;#pid /tmp/nginx.pid;#g' /etc/nginx/nginx.conf && \
     envsubst "$(printenv | cut -d= -f1 | grep TFW_ | sed -e 's/^/$/g')" \
-        < /etc/nginx/sites-available/default > /etc/nginx/sites-available/default
-
-WORKDIR /data/
-COPY src/frontend /data/
-RUN yarn install --frozen-lockfile
-RUN yarn build --no-progress && \
+        < /etc/nginx/sites-available/default > /etc/nginx/sites-available/default &&\
     mv /data/dist ${TFW_FRONTEND_DIR}
 
 USER ${AVATAO_USER}