Use best practices for Dockerfiles (#180)

db/Dockerfile

@@ -1,18 +1,29 @@
 FROM postgres:9.4
 
+# Install some packages to use WAL
 RUN apt-get update \
-    && apt-get install -y python-dev libffi-dev libssl-dev lzop pv daemontools curl build-essential \
+    && apt-get install -y \
+      build-essential \
+      curl \
+      daemontools \
+      libffi-dev \
+      libssl-dev \
+      lzop \
+      pv \
+      python-dev \
     && curl --silent --show-error --retry 5 https://bootstrap.pypa.io/get-pip.py | python \
     && pip install 'wal-e<1.0.0' \
-    && apt-get remove -y build-essential python-dev \
+    && apt-get remove -y \
+      build-essential \
+      python-dev \
     && apt-get autoremove -y \
     && apt-get clean \
-    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+    && rm -rf /var/lib/apt/lists/* /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin /tmp/* /var/tmp/*
 
+# Add wale script
 COPY setup-wale.sh /docker-entrypoint-initdb.d/
-COPY docker-entrypoint1.sh /
-RUN chmod +x /docker-entrypoint1.sh
-
-ENTRYPOINT ["/docker-entrypoint1.sh"]
 
+# Add and configure entrypoint and command
+COPY entrypoint.sh /
+ENTRYPOINT ["/entrypoint.sh"]
 CMD ["postgres"]