title: Integrate fabric.js in Spree
body: <p>In an attempt to use fabric.js with Spree, I came accross the Javascript error that the <code>require</code> instruction is undefined in the file <code>build.js</code> (top line). I could use the gem requirejs-rails to solve this problem, but it represents quite a change to Spree. Therefore, I would like to know if anybody came accross this problem and could provide a nifty solution?</p>