docs: added link to component options spec (vuejs#1192)

kraigh · yyx990803 · commit df147a7a77bd · 2018-03-23T17:20:18.000-04:00
* Added link to component options spec

* Update spec.md
diff --git a/docs/en/start/spec.md b/docs/en/start/spec.md
@@ -58,7 +58,7 @@ More details can be found in [Using Pre-Processors](../configurations/pre-proces
 
 - The script is executed in a CommonJS like environment (just like a normal `.js` module bundled via webpack), which means you can `require()` other dependencies. And with ES2015 support, you can also use the `import` and `export` syntax.
 
-- The script must export a Vue.js component options object. Exporting an extended constructor created by `Vue.extend()` is also supported, but a plain object is preferred.
+- The script must export a Vue.js [component options object](https://vuejs.org/v2/api/#Options-Data). Exporting an extended constructor created by `Vue.extend()` is also supported, but a plain object is preferred.
 
 #### `<style>`
 
