docs: add demos page (#828)

docs/developers/demos.md

@@ -0,0 +1,33 @@
+---
+sidebar_label: Demos on Celestia
+description: A collection of various demos built on Celestia.
+---
+
+# Demos on Celestia
+
+<!-- markdownlint-disable MD013 -->
+
+This page is a collection of demos built by the community on top of
+Celestia. If you'd like to add yours to the list, please [edit this page](https://github.com/celestiaorg/docs/edit/main/docs/developers/demos.md)
+and make a pull request to do so!
+
+## Celestia
+
+* macOS light node client by [@JoshCStein](https://twitter.com/JoshCStein) - [quasarapp.xyz](https://quasarapp.xyz)
+* RPC CLI tutorial with an on-chain SVG by [@JoshCStein](https://twitter.com/JoshCStein) - [based64.xyz](https://based64.xyz)
+
+## OP Stack testnet
+
+* gm portal, a smart contract demo by [@JoshCStein](https://twitter.com/JoshCStein) - [gmportal.xyz](https://gmportal.xyz)
+* generative art marketplace by [@JoshCStein](https://twitter.com/JoshCStein) - [buildmarket.xyz](https://buildmarket.xyz)
+* pessimistic loogies SVG NFT built with scaffold-eth by [@JoshCStein](https://twitter.com/JoshCStein) - [pessimistic.co](https://pessimistic.co)
+
+## Rollkit
+
+* frontend for gm world tutorial by [@JoshCStein](https://twitter.com/JoshCStein) - [rollkit-frontend.vercel.app](https://rollkit.dev/docs/tutorials/gm-world/)
+* ethermint demo by [@JoshCStein](https://twitter.com/JoshCStein) - [saymoo.lol](https://saymoo.lol/) (deprecated)
+* [NFT collection](https://tiny-base-4787.on.fleek.co/) made with Thirdweb SDK and their widgets by [@JoshCStein](https://twitter.com/JoshCStein) -  (deprecated)
+
+## Miscellaneous
+
+* [buildwhatever.com](https://buildwhatever.com) by [@JoshCStein](https://twitter.com/JoshCStein)

sidebars.js

@@ -450,6 +450,11 @@ const sidebars = {
         }
 			]
     },
+    {
+      type: "doc",
+      label: "Demos on Celestia",
+      id: "developers/demos",
+    },
     {
       type: "doc",
       label: "Integrate Celestia",