Install gnupg for fetching keys first

Dockerfile

@@ -5,17 +5,13 @@ MAINTAINER Tim Sutton<tim@kartoza.com>
 RUN  export DEBIAN_FRONTEND=noninteractive
 ENV  DEBIAN_FRONTEND noninteractive
 RUN  dpkg-divert --local --rename --add /sbin/initctl
-#RUN  ln -s /bin/true /sbin/initctl
-
-# Use local cached debs from host (saves your bandwidth!)
-# Change ip below to that of your apt-cacher-ng host
-# Or comment this line out if you do not with to use caching
-ADD 71-apt-cacher-ng /etc/apt/apt.conf.d/71-apt-cacher-ng
 
+RUN apt-get -y update
+RUN apt-get -y install gnupg
 #RUN echo "deb http://archive.ubuntu.com/ubuntu trusty main universe" > /etc/apt/sources.list
 # Add the PostgreSQL PGP key to verify their Debian packages.
 # It should be the same key as https://www.postgresql.org/media/keys/ACCC4CF8.asc
-RUN apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys B97B0AFCAA1A47F044F244A07FCC7D46ACCC4CF8
+RUN apt-key adv --keyserver hkps://p80.pool.sks-keyservers.net:80 --recv-keys B97B0AFCAA1A47F044F244A07FCC7D46ACCC4CF8
 # Add PostgreSQL's repository. It contains the most recent stable release
 #     of PostgreSQL, ``9.5``.
 RUN echo "deb http://apt.postgresql.org/pub/repos/apt/ jessie-pgdg main" > /etc/apt/sources.list.d/pgdg.list
@@ -27,9 +23,7 @@ RUN apt-get -y install ca-certificates rpl pwgen
 # We add postgis as well to prevent build errors (that we dont see on local builds)
 # on docker hub e.g.
 # The following packages have unmet dependencies:
-# postgresql-9.3-postgis-2.1 : Depends: libgdal1h (>= 1.9.0) but it is not going to be installed
-#                              Recommends: postgis but it is not going to be installed
-RUN apt-get install -y postgresql-9.5-postgis-2.2 netcat
+RUN apt-get install -y postgresql-9.5-postgis-2.2 
 
 # Open port 5432 so linked containers can see them
 EXPOSE 5432