Add basic user docs for npm registry

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

doc/user/project/index.md

@@ -89,6 +89,7 @@ website with GitLab Pages
   your code blocks, overriding GitLab's default choice of language
 - [Badges](badges.md): Badges for the project overview
 - [Maven packages](packages/maven_repository.md): Your private Maven repository in GitLab **[PREMIUM]**
+- [NPM packages](packages/npm_registry.md): Your private NPM package registry in GitLab **[PREMIUM]**
 - [Code owners](code_owners.md): Specify code owners for certain files **[STARTER]**
 - [License Management](merge_requests/license_management.md): Approve and blacklist licenses for projects **[ULTIMATE]**
 

doc/user/project/packages/npm_registry.md

+# GitLab NPM Registry **[PREMIUM]**
+
+> Introduced in [GitLab Premium](https://about.gitlab.com/pricing/) 11.7.
+
+With the GitLab NPM Registry, every
+project can have its own space to store its NPM packages.
+
+![GitLab NPM Registry](img/npm_package_view.png)
+
+NOTE: **Note:**
+Only scoped packages are supported. 
+
+## Enabling NPM Registry
+
+NOTE: **Note:**
+This option is available only if your GitLab administrator has
+[enabled Packages feature](../../../administration/maven_repository.md).
+
+In order to use the GitLab NPM Registry, you must enable the Packages feature.
+To enable (or disable) it:
+
+1. Navigate to your project's **Settings > General > Permissions**.
+1. Find the "Packages" feature and enable it.
+1. Click on **Save changes** for the changes to take effect.
+
+You should then be able to see the **Packages** section on the left sidebar.
+Next, you must configure your project to authorize with the GitLab NPM
+registry.
+
+## Package naming convention
+
+Note that **only packages that have the same path as the project** are supported.
+
+| Project | Package | Supported |
+| ------- | ------- | --------------------------------- |
+| `foo/bar`              | `@foo/bar`              | Yes |
+| `gitlab-org/gitlab-ce` | `@foo/bar`              | No  |
+| `gitlab-org/gitlab-ce` | `@gitlab-org/gitlab-ce` | Yes |
+
+## Authenticating to the GitLab NPM Registry
+
+If a project is private or you want to upload NPM package to GitLab,
+credentials will need to be provided for authorization. Support is available for
+[oauth tokens](#authenticating-with-an-oauth-token) only.
+
+### Authenticating with an oauth token
+
+To authenticate with a [oauth token](../../../api/oauth2.md),
+add a corresponding section to your `.npmrc` file:
+
+```
+; Set URL for your scoped packages. 
+; For example package with name `@foo/bar` will use this URL for download 
+@foo:registry=https://gitlab.com/api/v4/packages/npm/
+
+; Add OAuth token for scoped packages URL. This will allow you to download
+; `@foo/` packages from private projects.  
+//localhost:3001/api/v4/packages/npm/:_authToken=1da4f6691c92a543f7416b8fe013357fda23b0730466841311b89809a51349ce
+
+; Add OAuth token for uploading to the registry. Replace `YOUR_PROJECT_ID`
+; with a project you want your package uploaded to. 
+//gitlab.com/api/v4/projects/YOUR_PROJECT_ID/packages/npm/:_authToken=YOUR_OAUTH_TOKEN
+```
+
+You should now be able to download and upload NPM packages to your project.
+
+## Uploading packages
+
+Before you will be able to upload a package, you need to specify registry for NPM. 
+To do this, you need to add next section to the bottom of `package.json`: 
+
+```json
+  "publishConfig": {
+    "registry":"https://gitlab.com/api/v4/projects/YOUR_PROJECT_ID/packages/npm/"
+  }
+```
+
+Once you added it and have set up the [authorization](#authorizing-with-the-gitlab-npm-registry),
+test to upload an NPM package from a project of yours:
+
+```sh
+npm publish
+```
+
+You can then navigate to your project's **Packages** page and see the uploaded
+packages or even delete them.