Install ca-certificates by default.

Requested in nginx#12 and seen
as used in https://github.com/jwilder/nginx-proxy.

Author: thresheek

Dockerfile

@@ -7,7 +7,9 @@ RUN echo "deb http://nginx.org/packages/mainline/debian/ wheezy nginx" >> /etc/a
 
 ENV NGINX_VERSION 1.7.9-1~wheezy
 
-RUN apt-get update && apt-get install -y nginx=${NGINX_VERSION} && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && \
+    apt-get install -y ca-certificates nginx=${NGINX_VERSION} && \
+    rm -rf /var/lib/apt/lists/*
 
 # forward request and error logs to docker log collector
 RUN ln -sf /dev/stdout /var/log/nginx/access.log