Add documentation concerning node.js & package versions about backbone-relational-tutorial

[antoviaque]

Thanks for noticing and reporting this - sounds like a good change to integrate to the package.json file, or upgrading the tutorial to support the latest version of nodejs. Btw pull requests are welcome for either solutions : )

[younes0]

I don't think that upgrading the tutorial to latest version is worth since people can easily change their node.js version with this tool: https://github.com/creationix/nvm
I can make a PR concerning this matter in the documentation if you agree.

[pellekrogholt]

+1 for some documentation on that

i get

$ node app
[Error: Module version mismatch, refusing to load.]
[Error: Cannot find module './build/default/DTraceProviderBindings']
[Error: Cannot find module './build/Debug/DTraceProviderBindings']

node.js:201
    throw e; // process.nextTick error, or 'error' event on first tick
      ^
Error: Cannot find module 'retry'
at Function._resolveFilename (module.js:332:11)
at Function._load (module.js:279:25)
at Module.require (module.js:354:17)
at require (module.js:370:17)
at Object.<anonymous> (/Users/pelle/dev/backbone_playground/backbone-relational-tutorial/node_modules/restify/lib/clients/http_client.js:14:13)
at Module._compile (module.js:441:26)
at Object..js (module.js:459:10)
at Module.load (module.js:348:31)
at Function._load (module.js:308:12)
at Module.require (module.js:354:17)
bash-3.2$ node --version
v0.6.12

but thats probably becase i don't know how to set up npm and node v0.6.12 in conjunction...