Add manual ruby install instructions

Default ruby from ubuntu (1.9.3-p0) doesnt work.
Merge pull request #39 from RaymiiOrg/patch-1

Add manual ruby install instructions
Clearify readme.
Add Dockerfile
Dependencies from readme.
Don't need libmysql
Can use only single description.
curl download seems to ends up in the wrong directory
Revert "curl download seems to ends up in the wrong directory"

This reverts commit 7e6083b975f892a1b4f3ad2698e94bc79d0902c4.
Hardcode path for configure.
debug info
pwd is not preserved between RUN commands.
Forgot to add libicu-dev
Make key creation non-interactive.
Try to make it non-interactive
The tilde was not the problem.
Need to inject so no literal.
Better debug info.
Need to inject variables.
Quite different now.