add wagtail_cache_block (#138)

README.md

@@ -92,6 +92,7 @@ Awesome Wagtail [![Awesome](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38
 - [Wagtail Code Block](https://github.com/FlipperPA/wagtailcodeblock) - StreamField code blocks for the Wagtail CMS with real-time PrismJS Syntax Highlighting.
 - [Wagtail Blocks](https://github.com/ibrahimawadhamid/wagtail_blocks) - A Collection of awesome Wagtail CMS stream-field blocks and Charts.
 - [Wagtail UI Plus](https://github.com/davidcondenl/wagtailuiplus) - Several UI improvements to the Wagtail editor interface for StreamFields and StreamBlocks.
+- [Wagtail Cache Block](https://github.com/AccordBox/wagtail_cache_block) - A templatetag which add HTML fragment cache to your StreamField block
 
 ### Static site generation