Missing dependencies in dockerfile

[ocelik111]

Hello, I was running through the quickstart guide and the docker build was not completing, I noticed in the dockerfile some dependencies were missing (libssl-dev and rapidjson-dev) and added them to line 6. Running with the added dependencies completed the build.

RUN apt-get update && apt-get install -y build-essential ccache bison flex libboost-all-dev libssl-dev rapidjson-dev cmake

[Seifert69]

If you have the time to do a pull request I'd be very grateful :-) If not, I'll get around to it. Thanks!

[ocelik111]

#357 here ya go chief