feat: add fadeIn animation story

.storybook/animate.stories.js

@@ -0,0 +1,25 @@
+import {createElement as h} from 'react';
+import {storiesOf} from '@storybook/react';
+const {action} = require('@storybook/addon-actions');
+const {linkTo} = require('@storybook/addon-links');
+const {create} = require('../index');
+const {addon: addonRule} = require('../addon/rule');
+const {addon: addonKeyframes} = require('../addon/keyframes');
+const {addon: addonFadeIn} = require('../addon/animate/fadeIn');
+
+const nano = create();
+addonRule(nano);
+addonKeyframes(nano);
+addonFadeIn(nano);
+const {rule} = nano;
+
+var className = rule({
+    width: '200px',
+    height: '200px',
+    background: 'red',
+});
+
+storiesOf('Addons/Animate', module)
+    .add('fadeIn', () =>
+        h('div', {className: 'fadeIn' + className}, 'Hello world')
+    )

addon/animate/fadeIn.js

@@ -16,7 +16,7 @@ exports.addon = function (renderer) {
         },
 
         '.fadeIn': {
-            animationName: 'fadeIn',
+            animation: 'fadeIn .4s linear',
         }
     });
 };