feat: Add DevContainer, EditorConfig, and Justfile

Introduces a comprehensive local development environment setup:

- Adds an `.editorconfig` file for consistent coding styles.
- Implements a VS Code DevContainer configuration (`.devcontainer/devcontainer.json`)
  using a Ruby 3.4 image, with VS Code extensions for Ruby,
  installation of 'just', and automatic bundle install.
- Creates a `Justfile` with common development tasks such as `setup`,
  `console`, and `list`.
- Updates `README.md` to include a section on the new development
  environment setup.

Author: google-labs-jules[bot]

.devcontainer/devcontainer.json

@@ -0,0 +1,32 @@
+{
+  "name": "Ruby Dev Container",
+  "image": "mcr.microsoft.com/devcontainers/ruby:0-3.4-bullseye",
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "rebornix.Ruby",
+        "Shopify.ruby-lsp",
+        "EditorConfig.EditorConfig",
+        "yzhang.markdown-all-in-one",
+        "redhat.vscode-yaml",
+        "esbenp.prettier-vscode"
+      ],
+      "settings": {
+        "terminal.integrated.shell.linux": "/bin/bash",
+        "[ruby]": {
+          "editor.defaultFormatter": "Shopify.ruby-lsp",
+          "editor.formatOnSave": true
+        }
+      }
+    }
+  },
+  "features": {
+    // If a standard feature for 'just' becomes available, it could be listed here.
+    // For example: "ghcr.io/devcontainers-contrib/features/just:1": {}
+  },
+  // Using onCreateCommand to ensure 'just' is available when the container is ready.
+  // This command runs inside the container.
+  "onCreateCommand": "sudo apt-get update && sudo apt-get install -y curl && sudo curl --proto '=https' --tlsv1.2 -sSf https://just.systems/install.sh | sudo bash -s -- --to /usr/local/bin",
+  "postCreateCommand": "bundle install",
+  "remoteUser": "vscode"
+}

.editorconfig

@@ -0,0 +1,18 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.{yaml,yml}]
+indent_size = 2

Justfile

@@ -0,0 +1,29 @@
+# Justfile for controller_setter_pattern
+
+# Default task: list available commands or run tests
+default: test
+
+# Setup development environment
+setup:
+    bundle install
+
+# Run RSpec tests
+test:
+    bundle exec rspec
+
+# Run a Ruby console session
+console:
+    bundle exec irb
+
+# Placeholder for linter (e.g., RuboCop)
+lint:
+    echo "Linter not yet configured. Add RuboCop or other linter."
+
+# List available tasks (simple version)
+list:
+    @echo "Available tasks:"
+    @echo "  setup    - Install dependencies"
+    @echo "  test     - Run RSpec tests"
+    @echo "  console  - Start IRB console"
+    @echo "  lint     - Run linter (not yet configured)"
+    @echo "  list     - List available tasks"

README.md

@@ -6,14 +6,24 @@
 
 Pattern for assign instance variables in controllers for use in views, etc.
 
-## Instalation
+## Installation
 
 Add `controller_setter_pattern` to your Gemfile:
 
 ```ruby
 gem "controller_setter_pattern"
 ```
 
+## Development Environment
+
+This project includes a [VS Code DevContainer](https://code.visualstudio.com/docs/remote/containers) configuration for a consistent development environment.
+Open this project in a DevContainer to automatically get all dependencies and tools set up.
+
+Common development tasks are managed using a `Justfile`. To see available commands, run:
+```sh
+just list
+```
+
 ## Basic usage
 
 Before setter pattern: