Are people just throwing out random programming languages?
Why would he need Python PHP and Perl? These are all server side languages, you'll likely only need one and not all three.
Ruby is all purpose and can be used for both client and server side scripting.
If you want to LEARN, you should start with the easy ones, HTML and CSS. Once you have that down begin Javascript and PHP or Python.
Once you know those 4 HTML, CSS, Javascript and PHP/Python all future languages will be that much easier to learn. They start to become very similar and you can start reading code like reading a book.
This will get you started with a dice site, if you are going for a full blown casino with graphics you'll need a team for sure.
I never said OP has to learn ALL of them. I said to choose ONE and choose it well.