message: Improvements to PostgreSQL docker image
  Bump PostgreSQL to v10
  Use alpine image
  Switch to curl
diff: -FROM mdillon/postgis:9.6
  +FROM mdillon/postgis:10-alpine
  -# Copy the pointer to the latest pg_dump
  COPY latest /tmp/latest
  -# Download and decompress latest pg_dump into image to be loaded on container startup
  -RUN apt-get update && \
  - apt-get install wget -y && \
  - wget -nv -O - $(cat /tmp/latest) > /docker-entrypoint-initdb.d/_postcodesiodata.sql.gz
  +RUN mkdir -p /docker-entrypoint-initdb.d/ && \
  + apk add --no-cache curl && \
  + curl -o /docker-entrypoint-initdb.d/_postcodesiodata.sql.gz $(cat /tmp/latest)
  