docs: add section for nuxthub deploy in ci/cd

Author: atinux

docs/content/1.docs/1.getting-started/3.deploy.md

@@ -67,6 +67,33 @@ The command will:
 You can also install the [NuxtHub CLI](https://github.com/nuxt-hub/cli) globally with: `npm i -g nuxthub`.
 ::
 
+### Usage with CI/CD
+
+::tip
+If you are using GitHub for your project, jump to the [Github Action](#github-action) section.
+::
+
+::important
+The `nuxthub deploy` command is designed to run **non-interactively** in CI/CD environments. It won’t prompt for additional input (such as logging in or linking the project). As long as the required environment variables are set, deployment will proceed automatically.
+::
+
+To integrate the `nuxthub deploy` command within your CI/CD pipeline, set the following environment variables:
+- `NUXT_HUB_PROJECT_KEY` – Your project key available in:
+  - Your project settings in the [NuxtHub Admin](https://admin.hub.nuxt.com)
+  - Your `.env` file (if you ran `npx nuxthub link`)
+- `NUXT_HUB_USER_TOKEN` – Your personal token, available in **User settings** → **Tokens** in the [NuxtHub Admin](https://admin.hub.nuxt.com)
+
+**Example command:**
+```bash [Terminal]
+NUXT_HUB_PROJECT_KEY=<my-project-key> NUXT_HUB_USER_TOKEN=<my-user-token> npx nuxthub deploy
+```
+
+This will authenticate your user and link your NuxtHub project for deployment.
+
+::note 
+For security, **do not hardcode these values**. Instead, store them as environment variables in your CI/CD pipeline.
+::
+
 ## GitHub Action
 
 After linking a GitHub repository to your project, NuxtHub automatically adds a GitHub Actions workflow to automatically deploy your application on every commit using the [NuxtHub GitHub Action](https://github.com/marketplace/actions/deploy-to-nuxthub).