Typo fixing(README) (#6681)

README.md

@@ -40,7 +40,7 @@ Our minimalist "Persona" theme gets you going right away, no coding experience r
 ## How can I follow along/contribute?
 
 * If you are a developer, feel free to check out the source and submit pull requests. We also have a wide array of [plugins](http://community.nodebb.org/category/7/nodebb-plugins) which would be a great starting point for learning the codebase.
-* If you are a designer, [NodeBB needs themes](http://community.nodebb.org/category/10/nodebb-themes)! NodeBB's theming system allows extention of the base templates as well as styling via LESS or CSS. NodeBB's base theme utilizes [Bootstrap 3](http://getbootstrap.com/) but themes can choose to use a different framework altogether.
+* If you are a designer, [NodeBB needs themes](http://community.nodebb.org/category/10/nodebb-themes)! NodeBB's theming system allows extension of the base templates as well as styling via LESS or CSS. NodeBB's base theme utilizes [Bootstrap 3](http://getbootstrap.com/) but themes can choose to use a different framework altogether.
 * If you know languages other than English you can help us translate NodeBB. We use [Transifex](https://www.transifex.com/projects/p/nodebb/) for internationalization.
 * Please don't forget to **like**, **follow**, and **star our repo**! Join our growing [community](http://community.nodebb.org) to keep up to date with the latest NodeBB development.