add notice on Ember consulting to README

README.md

@@ -2,6 +2,11 @@
 
 This repository contains the sample projects for Mainmatter' Ember.js workshop.
 
+> [!NOTE]
+> This workshop has been written by [Mainmatter](https://mainmatter.com/).  
+> It's one of the trainings in [our portfolio of workshops](https://mainmatter.com/services/workshops/).  
+> We also offer consulting, training, and team augmentation for Ember.js – check out our [website](https://mainmatter.com/ember-consulting/) to learn more!
+
 * [`tomster-player`](https://github.com/simplabs/ember-workshop/tree/tomster-player/tomster-player)
   contains the main sample application, the Tomster music player; this app is
   also deployed at https://brave-gates-bc4632.netlify.com