Recommended frameworks and languages for building a social networking site?

Hey all,

Apologies if this is a bit repetitive of other questions on here, but I still wasn't entirely sure which route to take after reading some of the other answers...

My front-end knowledge is good, I work with HTML, CSS and Javascript on a daily basis, but my back-end knowledge is severely lacking, so I'm wanting to build a social networking site as a way of improving my back-end skills and giving myself a goal to work towards in the process.

While I'm starting this purely as a personal development project, I intend to build it with a possible future launch in mind, even if it's just for my friends and I to use.

My initial thoughts were that I'd like to build it using Ruby on Rails, but I don't really know how else to approach it.

Features that I would definitely like to include would be:

• Individual profile pages incl. awards/points system (I suppose similar to Treehouse - I'd like there to be some form of points based on user interaction)

• Users Forum

• Ability to create and share documents

• a groups system where users can become members of specific groups/ add content/posts

That's all I can think of off the top of my head, but really, I don't know which direction to start in first!

Thanks,

G