Add alpine base image

- Inspired by #408
- Possible solution for #543

Dockerfile.alpine

@@ -0,0 +1,31 @@
+FROM nginx:1.11.3-alpine
+MAINTAINER Jason Wilder mail@jasonwilder.com
+
+# Install wget and install/updates certificates
+RUN apk add --no-cache --virtual .run-deps \
+    ca-certificates bash wget \
+    && update-ca-certificates
+
+# Configure Nginx and apply fix for very long server names
+RUN echo "daemon off;" >> /etc/nginx/nginx.conf \
+ && sed -i 's/^http {/&\n    server_names_hash_bucket_size 128;/g' /etc/nginx/nginx.conf
+
+# Install Forego
+ADD https://github.com/jwilder/forego/releases/download/v0.16.1/forego /usr/local/bin/forego
+RUN chmod u+x /usr/local/bin/forego
+
+ENV DOCKER_GEN_VERSION 0.7.3
+
+RUN wget --quiet https://github.com/jwilder/docker-gen/releases/download/$DOCKER_GEN_VERSION/docker-gen-alpine-linux-amd64-$DOCKER_GEN_VERSION.tar.gz \
+ && tar -C /usr/local/bin -xvzf docker-gen-alpine-linux-amd64-$DOCKER_GEN_VERSION.tar.gz \
+ && rm /docker-gen-alpine-linux-amd64-$DOCKER_GEN_VERSION.tar.gz
+
+COPY . /app/
+WORKDIR /app/
+
+ENV DOCKER_HOST unix:///tmp/docker.sock
+
+VOLUME ["/etc/nginx/certs"]
+
+ENTRYPOINT ["/app/docker-entrypoint.sh"]
+CMD ["forego", "start", "-r"]