Sample logical backup image. (#572)

* Sample logical backup image.

Based on the earlier work by Dmitry Dolgov @erthalion

docker/logical-backup/Dockerfile

@@ -0,0 +1,33 @@
+FROM ubuntu:18.04
+LABEL maintainer="Team ACID @ Zalando <team-acid@zalando.de>"
+
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+RUN apt-get update     \
+    && apt-get install --no-install-recommends -y \
+        apt-utils \
+        ca-certificates \
+        lsb-release \
+        pigz \
+        python3-pip \
+        python3-setuptools \
+        curl \
+        jq \
+        gnupg \
+    && pip3 install --no-cache-dir awscli --upgrade \
+    && echo "deb http://apt.postgresql.org/pub/repos/apt/ $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list \
+    && cat /etc/apt/sources.list.d/pgdg.list \
+    && curl --silent https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add - \
+    && apt-get update \
+    && apt-get install --no-install-recommends -y  \
+        postgresql-client-11  \
+        postgresql-client-10  \
+        postgresql-client-9.6 \
+        postgresql-client-9.5 \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY dump.sh ./
+
+ENV PG_DIR=/usr/lib/postgresql/
+
+ENTRYPOINT ["/dump.sh"]