Add deploy with Vercel button

README.md

@@ -2,6 +2,8 @@
 
 Spliit is a free and open source alternative to Splitwise. I created it back in 2022 as a side project to learn the Go language, but rewrote it with Next.js since.
 
+[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https%3A%2F%2Fgithub.com%2Fspliit-app%2Fspliit&project-name=my-spliit-instance&repository-name=my-spliit-instance&stores=%5B%7B%22type%22%3A%22postgres%22%7D%5D&)
+
 ## Features
 
 - [x] Create a group and share it with friends