docs(readme/deploy): add a vercel deploy instructions

backend/README.md

@@ -0,0 +1,28 @@
+# Anix Backend
+
+This is the backend for AniX, an unofficial WEB client for the Android app Anixart.
+
+It is using FastAPI and server as a proxy between app API and Web Client.
+
+## Deployment
+
+### Environment variables
+
+- API_PREFIX - sets the api prefix
+
+### Docker
+
+  [Refer the docker deployment from root README file](../README.md#docker-deployment)
+
+## Vercel
+
+1. fork the repository
+2. create a new project on vercel and set the root directory to backend
+3. (optionally) set API_PREFIX env variable
+4. click deploy
+
+### One-Click Deploy
+
+[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https://github.com/Radiquum/AniX/tree/main/backend)
+
+*note*: this will create a new repository