Update docs to reflect that sage 8 does not currently support node 6

[aried3r]

It's actually not sage itself that doesn't support it, but some dependencies, like node-sass (also this are not compatible with node 6 yet, also graceful-fs.

Until this is fixed, or Sage 9 is released, which changes a lot of things, I'd recommend putting
Node >= 0.12.x, < 6.x
into the documentation.

[ciromattia]

This is not actually true.
I'm using sage 8 with an updated node, and despite I had to mess in updating my -g packages, at the moment it works, though giving quite a bunch of node warnings in running gulp (I think the main offender here is node-sass and its dependencies)

[aried3r]

That's great to hear!
Do you mind sharing the steps you needed to take to get it running? Since it doesn't seem to work out of the box.

My main problem was (even after rebuilding node-sass) that main.scss was not being compiled to main.css, only throwing lots of JS stack traces.
Thus my site was left unstyled.

[ciromattia]

You have to rm -rf node_modules/* and then npm install again, because libsass needs new bindings.
Also, my package.json is now:

"devDependencies": {
    "asset-builder": "^1.1.0",
    "browser-sync": "^2.8.2",
    "del": "~2.2",
    "gulp": "^3.9.0",
    "gulp-autoprefixer": "~3.1",
    "gulp-changed": "^1.3.0",
    "gulp-concat": "^2.6.0",
    "gulp-cssnano": "^2.1.0",
    "gulp-flatten": "~0.2",
    "gulp-if": "~2.0",
    "gulp-imagemin": "^2.3.0",
    "gulp-inject": "^4.0.0",
    "gulp-jshint": "^2.0.0",
    "gulp-less": "^3.0.3",
    "gulp-plumber": "^1.0.1",
    "gulp-rename": "^1.2.2",
    "gulp-rev": "~7.0",
    "gulp-sass": "^2.0.1",
    "gulp-sourcemaps": "*",
    "gulp-svg2png": "~1.0",
    "gulp-svgmin": "^1.2.0",
    "gulp-svgstore": "~6.0",
    "gulp-uglify": "^1.2.0",
    "imagemin-pngcrush": "^4.1.0",
    "jshint": "^2.9.2",
    "jshint-stylish": "^2.0.1",
    "lazypipe": "^1.0.1",
    "merge-stream": "^1.0.0",
    "minimist": "^1.1.3",
    "run-sequence": "^1.1.2",
    "traverse": "^0.6.6",
    "wiredep": "~4.0.0"
  }

(svg stuff is for SVG sprites)
IIRC I have updated also a bunch of global packages, you can check your mileage with npm -g outdated.