Add Paddings addon to addon gallery (#9647)

Add Paddings addon to addon gallery

docs/src/pages/addons/addon-gallery/index.md

@@ -90,6 +90,10 @@ You can even run these tests inside a CI box.
 With this addon, you can showcase multiple components (or varying component states) within 1 story.
 Break your stories down into smaller categories (chapters) and subcategories (sections) for more organizational goodness.
 
+### [Paddings](https://github.com/rbardini/storybook-addon-paddings)
+
+Add different paddings to your preview. Useful for checking how components behave when surrounded with white space.
+
 ### [Props Combinations](https://github.com/evgenykochetkov/react-storybook-addon-props-combinations)
 
 Given possible values for each prop, renders your component with all combinations of prop values.