Add Debian Jessie build image

This image is meant to be used to build packages for the Jessie release of Debian. See debian/nginx-build.

debian/jessie/Dockerfile

@@ -4,6 +4,7 @@ LABEL maintainer="ethitter"
 LABEL version="1.0"
 
 RUN echo "deb http://security.debian.org/ jessie/updates main" >> /etc/apt/sources.list
+RUN echo "deb http://httpredir.debian.org/debian/ jessie-backports main contrib non-free" >> /etc/apt/sources.list
 
 RUN apt-get update \
     && apt-get -yqqf --no-install-recommends install \
@@ -27,8 +28,9 @@ RUN apt-get update \
         libpcre3 \
         libpcre3-dev \
         libz-dev \
-        shellcheck \
         gnupg \
+    && apt-get -y --no-install-recommends install -t jessie-backports \
+        openssl \
         libssl-dev \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*