Updates to latest stable release.

Dockerfile

@@ -2,17 +2,17 @@
 FROM busybox:ubuntu-14.04
 MAINTAINER Werner Beroux <werner@beroux.com>
 
-# Install ngrok
-ADD https://dl.ngrok.com/ngrok_2.0.19_linux_amd64.zip /ngrok.zip
+# Install ngrok (latest official stable from https://ngrok.com/download).
+ADD https://bin.equinox.io/c/4VmDzA7iaHb/ngrok-stable-linux-amd64.zip /ngrok.zip
 RUN set -x \
  && unzip -o ngrok.zip -d /bin \
  && rm -f /ngrok.zip
 
-# Add config script
+# Add config script.
 COPY ngrok.yml /home/ngrok/.ngrok2/
 COPY entrypoint.sh /
 
-# Create non-root user
+# Create non-root user.
 RUN echo 'ngrok:x:6737:6737:Ngrok user:/home/ngrok:/bin/false' >> /etc/passwd
 RUN echo 'ngrok:x:6737:' >> /etc/group
 RUN chown ngrok:ngrok /home/ngrok