Dockerfile: switch to debian:stretch

This is needed because openjdk-8-jre-headless was not anymore on the
backport servers for jessie.

    + apt-get -t jessie-backports install -y bash openjdk-8-jre-headless unzip
    Reading package lists...
    Building dependency tree...
    Reading state information...
    E: Unable to locate package openjdk-8-jre-headless

This fixes #9.

Signed-off-by: Silvio Fricke <silvio.fricke@gmail.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/Dockerfile b/Dockerfile
index 2c1cb64..0fe7ea4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,14 +1,13 @@
-FROM debian:jessie
+FROM debian:stretch
 
 MAINTAINER Silvio Fricke <silvio.fricke@gmail.com>
 
 RUN set -ex \
     && mkdir -p /uploads /etc/apt/sources.list.d /var/cache/apt/archives/ \
-    && echo "deb http://ftp.debian.org/debian jessie-backports main" > /etc/apt/sources.list.d/jessie.backports.list \
     && export DEBIAN_FRONTEND=noninteractive \
     && apt-get clean \
     && apt-get update -y \
-    && apt-get -t jessie-backports install -y \
+    && apt-get install -y \
         bash \
         openjdk-8-jre-headless \
         unzip