Added missing demo link in further-react

Author: disarrayx

book/src/03_intro-react/index.md

@@ -1,4 +1,4 @@
-# Figma
+# Intro to React
 
 ## Presentation Slides
 **Authors: Alyssa Cheong & Giselle Putri | [Link to slides](https://www.canva.com/design/DAGg9E5TJSA/Ewax_jT81t8lqPaMTkc3Cg/edit) | [Link to repository](https://github.com/devsoc-unsw/devsoc-mail/tree/ws2/components)** 

book/src/04_further-react/index.md

@@ -1,8 +1,8 @@
-# Figma
+# Further React
 
 ## Presentation Slides
-**Authors: Lachlan Shoesmith | [Link to slides](https://www.canva.com/design/DAGSm5IgDSU/fRVbxTekEvoKCxAcG6VWCg/edit) | [Link to repo](https://github.com/devsoc-unsw/devsoc-mail/tree/ws3/react)**
+**Authors: Lachlan Shoesmith | [Link to slides](https://www.canva.com/design/DAGSm5IgDSU/fRVbxTekEvoKCxAcG6VWCg/edit) | [Link to demo repo](https://github.com/lachlanshoesmith/hookie-monster) | [Link to exercise repo](https://github.com/devsoc-unsw/devsoc-mail/tree/ws3/react)**
 
-Activities are in the README.md file in the repo.
+Activities are in the README.md file in the exercise repo.
 
 <iframe src="https://www.canva.com/design/DAGSm5IgDSU/zdxO-cKL9jfhvzayAk6-Aw/view?embed" frameborder="0" width="800" height="450" allowfullscreen="true" mozallowfullscreen="true" webkitallowfullscreen="true"></iframe>