[exoframe-website] Add recipe for using build args

packages/exoframe-website/docs/recipes/buildargs.md

@@ -0,0 +1,40 @@
+---
+sidebar_position: 1
+---
+
+# Using Docker Build Arguments
+
+Sometimes, you might need to pass dynamic variables to your project during build time.
+One way to achieve this is through [Docker build arguments](https://docs.docker.com/build/guide/build-args/).
+
+Exoframe supports passing build arguments via the project config.
+
+The example below demonstrates the use of build args with a custom Dockerfile to build a Next.js project.
+For a complete Dockerfile example, refer to the [Next.js docs](https://nextjs.org/docs/pages/building-your-application/deploying#docker-image).
+
+**Dockerfile:**
+
+```Dockerfile
+# ... copy values from args to env vars so that Next.js can use them
+ARG GRAPHQL_URL=http://default.endpoint.com/v1
+ENV NEXT_PUBLIC_GRAPHQL_ENDPOINT=${GRAPHQL_URL}
+ARG SECRET_KEY
+ENV SECRET_KEY=${SECRET_KEY}
+
+# build app
+RUN npm run build
+
+# ... rest of Dockerfile
+```
+
+**Exoframe Project Config:**
+
+```json
+{
+  "name": "example-buildargs-project",
+  "buildargs": {
+    "GRAPHQL_URL": "https://graphql.endpoint.com/v1",
+    "SECRET_KEY": "@my-secret"
+  }
+}
+```