Slight improvement to the v1-alpha docs

Trying out an example like AppBar fails with

TypeError: this.context.styleManager is undefined
render
node_modules/material-ui/styles/withStyles.js:98

   95 | 
   96 | 
   97 | var classes = void 0;
>  98 | var renderedClasses = this.context.styleManager.render(styleSheet);
   99 | 
  100 | if (classesProp) {
  101 |   classes = (0, _extends3.default)({}, renderedClasses, (0, _keys2.default)(classesProp).reduce(function (acc, key) {

Wrapping that component in a <MuiThemeProvider/> (as mentioned in the Usage page) solves the issue.

But there might be people landing directly on that page or noobs like me that forget. Maybe add a generic App.js that ends up including the component ? Willing to do the work if it sounds fine.

[oliviertassinari]

I have updated the link to the usage section.

[oliviertassinari]

At least adding a link back to Usage would be good.

Do you mean for the warning message? Yes, that sounds like a good idea!