add postgres.Dockerfile

Signed-off-by: hwipl <33433250+hwipl@users.noreply.github.com>

postgres.Dockerfile

@@ -0,0 +1,4 @@
+FROM postgres:12.1
+
+# copy db init script into image
+COPY ["./scripts/funwar_initdb.sh", "/docker-entrypoint-initdb.d"]