Add stretch build

THis is purely copy-pasta from the Jessie build.

.gitlab-ci.yml

@@ -48,6 +48,24 @@ build-golang-dev:
     - docker push "$CI_REGISTRY_IMAGE/golang:latest-dev"
   except:
     - master
+     
+# Debian Stretch builds
+build-debian-stretch-build-master:
+  stage: deploy
+  script:
+    - docker build --pull -t "$CI_REGISTRY_IMAGE/debian:stretch" ./debian/stretch
+    - docker push "$CI_REGISTRY_IMAGE/debian:stretch"
+  only:
+    - master
+  when: manual
+
+build-debian-stretch-build-dev:
+  stage: deploy
+  script:
+    - docker build --pull -t "$CI_REGISTRY_IMAGE/debian:stretch-dev" ./debian/stretch
+    - docker push "$CI_REGISTRY_IMAGE/debian:stretch-dev"
+  except:
+    - master
 
 # Debian Jessie builds
 build-debian-jessie-build-master:

debian/stretch/Dockerfile

+FROM debian:stretch
+
+LABEL maintainer="ethitter"
+LABEL version="1.0"
+
+RUN echo "deb http://security.debian.org/ stretch/updates main" >> /etc/apt/sources.list
+
+RUN apt-get update \
+    && apt-get -yqqf --no-install-recommends install \
+        apt-transport-https \
+        lsb-release \
+        ca-certificates \
+        curl \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN curl -ssL -o /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
+RUN echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" > /etc/apt/sources.list.d/php.list
+
+RUN apt-get update \
+    && apt-get -y --no-install-recommends install \
+        git \
+        dh-make \
+        build-essential \
+        autoconf \
+        autotools-dev \
+        libpcre3 \
+        libpcre3-dev \
+        libz-dev \
+        gnupg \
+        libssl-dev \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*