Update Ruby to 3.3.7 and improve Docker setup: - Update Gemfile with …

Gemfile

@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
 
-gem 'builder'
-gem 'nokogiri'
-gem 'feedbag'
+gem 'builder', '~> 3.2'
+gem 'nokogiri', '~> 1.15.0'
+gem 'feedbag', '~> 0.9.13'

contributing.md

@@ -11,14 +11,49 @@ Please ensure your pull request adheres to the following guidelines:
 - After making changes to the README, run `bundle install` to install the dependencies and then the opml generation script (`./generate_opml.rb`) to update the opml file.
 
 ## Running the OPML Generation Script with Docker
-If you do not have Ruby readily available the following steps can be used to run the OPML generation script with Docker:
 
-```
-docker run -it -e LANG=C.UTF-8 --name=blogs ruby:2.5 /bin/bash
+If you do not have Ruby readily available, you can use Docker to run the OPML generation script. Follow these steps:
+
+```bash
+# 1. Pull and run the Ruby 3.3.7 container
+docker run -it -e LANG=C.UTF-8 --name=blogs ruby:3.3.7 /bin/bash
+
+# 2. Inside the container, update RubyGems and install bundler
+gem update --system
+gem install bundler
+
+# 3. Clone the repository
 git clone https://github.com/<username>/engineering-blogs.git
 cd engineering-blogs
-gem install bundler
+
+# 4. Remove existing Gemfile.lock to ensure fresh installation
+rm -f Gemfile.lock
+
+# 5. Install dependencies
 bundle install
+
+# 6. Generate the OPML file
 ruby generate_opml.rb
+
+# 7. Exit the Docker container (type 'exit' or press Ctrl+D)
+exit
+
+# 8. Now in your host machine terminal, copy the generated file
+# Make sure to include the dot (.) at the end of the command
 docker cp blogs:/engineering-blogs/engineering_blogs.opml .
+
+# 9. Clean up the Docker container
+docker rm blogs
 ```
+
+### Important Notes:
+
+1. **Dependencies**: If you encounter any issues with dependencies, make sure you're using the latest versions specified in the Gemfile. The instructions above include removing the Gemfile.lock to ensure all dependencies are properly resolved for Ruby 3.3.7.
+
+2. **Docker Commands**:
+   - Make sure to exit the Docker container before running the `docker cp` command, as this command needs to be run from your host machine's terminal, not from inside the container.
+   - The `docker cp` command requires two arguments: the source path and the destination path. The dot (.) at the end of the command is important as it specifies the current directory as the destination.
+
+3. **Troubleshooting**:
+   - If you encounter any issues with the Docker container, you can remove it using `docker rm -f blogs` and start fresh.
+   - Make sure you have sufficient disk space and Docker is running properly on your system.