Implement support for multiple PHP versions

This commit provides docker images and scripts to support multiple
Debian and PHP releases via containers.

buster_php7/Dockerfile-pgsql

@@ -0,0 +1,15 @@
+FROM gnuviech/buster_php7-base:latest
+LABEL maintainer="jan@dittberner.info"
+
+RUN apt-get update \
+    && DEBIAN_FRONTEND=noninteractive \
+    apt-get install -y --no-install-recommends \
+    php-mysql \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*.*
+
+COPY start-fpm.sh /usr/local/sbin
+COPY fpm-pool.conf.tmpl /usr/local/etc
+
+ENTRYPOINT ["/usr/bin/dumb-init", "--"]
+CMD ["/usr/local/sbin/start-fpm.sh"]