Update README to refer to Propshaft support

Author: spohlenz

README.md

@@ -3,7 +3,7 @@ Rails Integration for TinyMCE
 
 The `tinymce-rails` gem integrates the [TinyMCE](https://www.tiny.cloud/) editor with the Rails asset pipeline.
 
-This gem is compatible with Rails 5.0 and higher.
+This gem is compatible with Rails 5.1 and higher.
 
 This is the branch for TinyMCE 5. Please see the [`main`](https://github.com/spohlenz/tinymce-rails) branch for TinyMCE 7, and alternate branches for [TinyMCE 6](https://github.com/spohlenz/tinymce-rails/tree/tinymce-6), [TinyMCE 4](https://github.com/spohlenz/tinymce-rails/tree/tinymce-4) & [TinyMCE 3.5.x](https://github.com/spohlenz/tinymce-rails/tree/tinymce-3).
 
@@ -58,7 +58,7 @@ See the [TinyMCE 5 Documentation](https://www.tiny.cloud/docs/configure/) for a
 
 Use *one* of the following options to include TinyMCE assets.
 
-(1) Add to your application.js:
+(1) Add to your application.js (Sprockets only):
 
 ```js
 //= require tinymce
@@ -73,10 +73,14 @@ or (2) with jQuery integration:
 (3) The TinyMCE assets can be included on a per-page basis using the `tinymce_assets` helper:
 
 ```erb
-<%= tinymce_assets %>
-#=> <script type="text/javascript" src="/assets/tinymce.js">
+<%= tinymce_assets data: { turbo_track: "reload" } %>
+#=> <script type="text/javascript" src="/assets/tinymce.js" data-turbo-track="reload">
 ```
 
+When using Propshaft, the `tinymce_assets` helper adds multiple script tags including the pre-init code (available via the `tinymce_preinit` helper), as well as `tinymce/tinymce.js` and `tinymce/rails.js`. You may prefer to selectively include these manually depending on your requirements.
+
+For Sprockets, these are bundled together into one script tag.
+
 
 **4. Initialize TinyMCE**