docs: Add a note on docker for linux setup in prerequisites. (#618)

Author: tjholm

src/pages/getting-started/installation.mdx

@@ -12,10 +12,16 @@ Nitric relies on functionality from the following projects to help retrieve plug
 Please follow these links to the official installation steps for each.
 
 - [Git](https://git-scm.com/)
-- [Docker](https://docs.docker.com/get-docker/) _(deployments only)_
-- [Docker Buildx](https://github.com/docker/buildx/) _(deployments only)_
+- [Docker](https://docs.docker.com/get-docker/)
+- [Docker Buildx](https://github.com/docker/buildx/)
 - [Pulumi](https://www.pulumi.com/docs/cli/) _(for deployments, only needed if using the default providers)_
 
+<Note>
+  When setting up docker on Linux be sure to follow the [post-installation
+  steps](https://docs.docker.com/engine/install/linux-postinstall/) so you can
+  run docker as a non-root user.
+</Note>
+
 ## Installing the Nitric CLI
 
 <InstallNitric>

src/pages/reference/cli/installation.mdx

@@ -9,10 +9,16 @@ Nitric relies on functionality from the following projects to help retrieve plug
 Please follow these links to the official installation steps for each.
 
 - [Git](https://git-scm.com/)
-- [Docker](https://docs.docker.com/get-docker/) _(deployments only)_
-- [Docker Buildx](https://github.com/docker/buildx/) _(deployments only)_
+- [Docker](https://docs.docker.com/get-docker/)
+- [Docker Buildx](https://github.com/docker/buildx/)
 - [Pulumi](https://www.pulumi.com/docs/cli/) _(for deployments, only needed if using the default providers)_
 
+<Note>
+  When setting up docker on Linux be sure to follow the [post-installation
+  steps](https://docs.docker.com/engine/install/linux-postinstall/) so you can
+  run docker as a non-root user.
+</Note>
+
 ## Installing the Nitric CLI
 
 <CodeGroup>