Update README.md

Author: 38tter

README.md

@@ -1,6 +1,6 @@
 # kramdown-mermaid
 
-This is a gem for parsing [Mermaid syntax](https://mermaid.js.org/), and is an extension of kramdown.
+This is a gem for parsing [Mermaid syntax](https://mermaid.js.org/), and is an extension of [kramdown](https://kramdown.gettalong.org/).
 
 Currently, only parsing of [Entity Relationship Diagrams](https://mermaid.js.org/syntax/entityRelationshipDiagram.html) is supported, but we hope to support parsing of Class Diagrams and Sequence Diagrams and more in the future.