Update and improve docker image

This commit updates the docker image to be based on Debian 10 Buster.
The startup script waits until the database container becomes available.
Needed dependencies for building the PostgreSQL driver were added to the
docker image.

Dockerfile

@@ -1,12 +1,14 @@
-FROM debian:stretch
-LABEL maintainer "Jan Dittberner <jan@dittberner.info>"
+FROM debian:buster
+LABEL maintainer="Jan Dittberner <jan@dittberner.info>"
 
 RUN apt-get update \
     && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
+    build-essential \
     dumb-init \
     gettext \
     git \
     libpq-dev \
+    postgresql-client \
     python3-dev \
     python3-pip \
     && apt-get clean \
@@ -20,11 +22,12 @@ ENV LANG=C.UTF-8
 
 RUN python3 -m pip install -U pip && pip3 install pipenv
 
-COPY gnuviechadmin.sh /srv/
 COPY Pipfile Pipfile.lock /srv/gnuviechadmin/
 
 RUN pipenv install --system --deploy --ignore-pipfile --dev
 
+COPY gnuviechadmin.sh /srv/
+
 EXPOSE 8000
 VOLUME /srv/gnuviechadmin
 

gnuviechadmin.sh

@@ -2,6 +2,19 @@
 
 set -e
 
+DB_HOST="${GVA_PGSQL_HOST:-db}"
+DB_PORT="${GVA_PGSQL_PORT:-5432}"
+DB_USER="${GVA_PGSQL_USER:-gnuviechadmin}"
+DB_NAME="${GVA_PGSQL_DATABASE:-gnuviechadmin}"
+
+until pg_isready -q -h "${DB_HOST}" -p "${DB_PORT}" -U "${PG_USER}" -d "${DB_NAME}"
+do
+  echo -n "."
+  sleep 1
+done
+
+echo "db is ready"
+
 python3 manage.py compilemessages
 python3 manage.py collectstatic --noinput
 python3 manage.py migrate --noinput