Add `gnu-sed` note for macOS

diff --git a/docs/setup.md b/docs/setup.md
index af6abff100441c53a59b32b742050308f282c9e5..9a5d2bb819c27d6baa661247d45d98fdf464768f 100644 (file)
--- a/docs/setup.md
+++ b/docs/setup.md
@@ -33,6 +33,11 @@ steps described in [Docker setup](#docker_hub) automatically.
     $ bash -c "$(curl -L https://raw.githubusercontent.com/paperless-ngx/paperless-ngx/main/install-paperless-ngx.sh)"
     ```
 
+    !!! note
+
+        macOS users will need to install e.g. [gnu-sed](https://formulae.brew.sh/formula/gnu-sed) with support
+        for running as `sed`.
+
 ### From GHCR / Docker Hub {#docker_hub}
 
 1.  Login with your user and create a folder in your home-directory to have a place for your