Improve tutorial: extract Heroku deployment, fix versions, reorganize structure

Changes to tutorial.md:
1. Replaced Heroku deployment section (139 lines) with brief Deployment section linking to deployment guides
2. Updated versions: Ruby 2.7 → 3.0+, Rails 5.1.3 → 7.0+, RoR v13 → v16
3. Clarified Redux usage: tutorial demonstrates Redux, but basic installer uses Hooks (user choice)
4. Merged duplicate HMR sections into one cohesive section using ./bin/dev
5. Renamed "Other features" → "Going Further" with better organization:
   - Server Rendering (important)
   - Optional Configuration subsection (/client structure, Cloud9, RubyMine)

Changes to heroku-deployment.md:
1. Merged tutorial's detailed Heroku instructions with existing guide
2. Added note about older versions with link to current Heroku Rails 7 guide
3. Organized into clear sections: Create App, Buildpacks, Postgres, Puma, Node/Yarn, Assets, Deploy

Rationale:
- Tutorial was overwhelming with platform-specific deployment before core features
- Heroku content now in dedicated guide (reusable, maintainable)
- Clear separation: tutorial teaches React on Rails, deployment guides teach platforms
- Better progression: install → run → features → deploy → advanced

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ihabadham

docs/deployment/heroku-deployment.md

@@ -1,10 +1,26 @@
 # Heroku Deployment
 
+> **Note:** This guide is based on the working tutorial app at [reactrails.com](https://reactrails.com). While the instructions work, some versions referenced are older. For current Heroku best practices with Rails 7, see [Heroku's Rails 7 Guide](https://devcenter.heroku.com/articles/getting-started-with-rails7).
+
+## Create Your Heroku App
+
+_Assuming you can log in to heroku.com and have logged into your shell for Heroku._
+
+1. Visit [https://dashboard.heroku.com/new](https://dashboard.heroku.com/new) and create an app, say named `my-name-react-on-rails`:
+
+![06](https://cloud.githubusercontent.com/assets/20628911/17465014/1f29bf3c-5cf4-11e6-869f-4215987ae854.png)
+
+Run this command that looks like this from your new Heroku app
+
+```bash
+heroku git:remote -a my-name-react-on-rails
+```
+
 ## Heroku buildpacks
 
 React on Rails requires both a ruby environment (for Rails) and a Node environment (for Webpack), so you will need to have Heroku use multiple buildpacks.
 
-Assuming you have downloaded and installed the Heroku command-line utility and have initialized the app, you will need to tell Heroku to use both buildpacks via the command-line:
+Set heroku to use multiple buildpacks:
 
 ```bash
 heroku buildpacks:set heroku/ruby
@@ -13,6 +29,129 @@ heroku buildpacks:add --index 1 heroku/nodejs
 
 For more information, see [Using Multiple Buildpacks for an App](https://devcenter.heroku.com/articles/using-multiple-buildpacks-for-an-app)
 
+## Swap out sqlite for postgres
+
+Heroku requires your app to use Postgresql. If you have not set up your app
+with Postgresql, you need to change your app settings to use this database.
+
+Run the following command (in Rails 6+):
+
+```bash
+rails db:system:change --to=postgresql
+```
+
+If for any reason you want to do this process manually, run these two commands:
+
+```bash
+bundle remove sqlite3
+bundle add pg
+```
+
+![07](https://cloud.githubusercontent.com/assets/20628911/17465015/1f2f4042-5cf4-11e6-8287-2fb077550809.png)
+
+Now replace your `database.yml` file with this (assuming your app name is "ror").
+
+```yml
+default: &default
+  adapter: postgresql
+  username:
+  password:
+  host: localhost
+
+development:
+  <<: *default
+  database: ror_development
+
+# Warning: The database defined as "test" will be erased and
+# re-generated from your development database when you run "rake".
+# Do not set this db to the same as development or production.
+test:
+  <<: *default
+  database: ror_test
+
+production:
+  <<: *default
+  database: ror_production
+```
+
+Then you need to set up Postgres so you can run locally:
+
+```bash
+rake db:setup
+rake db:migrate
+```
+
+![08](https://cloud.githubusercontent.com/assets/20628911/17465016/1f3559f0-5cf4-11e6-8ab4-c5572e4644a5.png)
+
+Optionally you can add this line to your `routes.rb`. That way, your root page will go to the Hello World page for React On Rails.
+
+```ruby
+root "hello_world#index"
+```
+
+![09](https://cloud.githubusercontent.com/assets/20628911/17465018/1f3b685e-5cf4-11e6-93f8-105fc48517d0.png)
+
+## Configure Puma
+
+Next, configure your app for Puma, per the [instructions on Heroku](https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server).
+
+Create `./Procfile` with the following content. This is what Heroku uses to start your app.
+
+```
+web: bundle exec puma -C config/puma.rb
+```
+
+Note, newer versions of Rails create this file automatically. However, the [docs on Heroku](https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#config) have something a bit different, so please make it conform to those docs. As of 2020-06-04, the docs looked like this:
+
+`config/puma.rb`
+
+```rb
+workers Integer(ENV['WEB_CONCURRENCY'] || 2)
+threads_count = Integer(ENV['RAILS_MAX_THREADS'] || 5)
+threads threads_count, threads_count
+
+preload_app!
+
+rackup      DefaultRackup
+port        ENV['PORT']     || 3000
+environment ENV['RACK_ENV'] || 'development'
+
+on_worker_boot do
+  # Worker specific setup for Rails 4.1+
+  # See: https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#on-worker-boot
+  ActiveRecord::Base.establish_connection
+end
+```
+
+## Specify Node and Yarn versions
+
+Next, update your `package.json` to specify the version of yarn and node. Add this section:
+
+```json
+  "engines": {
+    "node": "16.19.0",
+    "yarn": "1.22.4"
+  },
+```
+
+## Deploy
+
+Then after all changes are done don't forget to commit them with git and finally, you can push your app to Heroku!
+
+```bash
+git add -A
+git commit -m "Changes for Heroku"
+git push heroku master
+```
+
+Then run:
+
+```bash
+heroku open
+```
+
+and you will see your live app and you can share this URL with your friends. Congrats!
+
 ## assets:precompile
 
 ### Shakapacker Webpack configuration