adding docker native healthcheck

Author: brentley

Dockerfile

@@ -3,7 +3,7 @@ FROM ruby:2.5-slim
 COPY Gemfile Gemfile.lock /usr/src/app/
 WORKDIR /usr/src/app
 
-RUN apt-get update && apt-get -y install libgmp3-dev ruby-dev build-essential libsqlite3-dev && \
+RUN apt-get update && apt-get -y install curl libgmp3-dev ruby-dev build-essential libsqlite3-dev && \
     bundle install && \
     apt-get autoremove -y --purge && \
     apt-get remove -y --auto-remove --purge ruby-dev libgmp3-dev build-essential libsqlite3-dev && \
@@ -17,5 +17,7 @@ RUN chmod +x /usr/src/app/startup.sh
 # RUN bundle update
 # RUN rm -vf /usr/src/app/Gemfile.lock
 
+HEALTHCHECK --interval=10s --timeout=3s \
+  CMD curl -f -s http://localhost:3000/health/ || exit 1
 EXPOSE 3000
 ENTRYPOINT ["bash","/usr/src/app/startup.sh"]