RuboCop plugin system via LintRoller

Adds a LintRoller-based plugin so RuboCop >= 1.72 can discover
and load the custom cops automatically through the `plugins:`
configuration. The legacy `require:` approach is preserved for
older RuboCop versions.

Author: AlfonsoUceda

README.md

@@ -247,18 +247,20 @@ end
 ## Using with RuboCop
 
 DatabaseValidations provides custom cops for RuboCop to help you consistently apply the improvements.
-To use all of them, use `rubocop --require database_validations/rubocop/cops` or add to your `.rubocop.yml` file:
+
+For RuboCop >= 1.72, add the plugin to your `.rubocop.yml` file:
 
 ```yaml
-require:
-  - database_validations/rubocop/cops
+plugins:
+  - database_validations:
+      require_path: rubocop-database_validations
 ```
 
-Or you case use some specific cop directly:
+For older versions of RuboCop, use `require` instead:
+
 ```yaml
 require:
-  - database_validations/rubocop/cop/belongs_to
-  - database_validations/rubocop/cop/uniqueness_of
+  - database_validations/rubocop/cops
 ```
 
 ## Development

config/rubocop-default.yml

@@ -0,0 +1,5 @@
+DatabaseValidations/BelongsTo:
+  Enabled: true
+
+DatabaseValidations/UniquenessOf:
+  Enabled: true

database_validations.gemspec

@@ -17,11 +17,14 @@ The main goal of the gem is to provide compatibility between database constraint
 and ActiveRecord validations with better performance and consistency."
   spec.homepage      = 'https://github.com/toptal/database_validations'
   spec.license       = 'MIT'
-  spec.files         = Dir['lib/**/*']
+  spec.files         = Dir['lib/**/*', 'config/**/*']
   spec.require_paths = ['lib']
   spec.required_ruby_version = '>= 3.2.0'
 
+  spec.metadata['default_lint_roller_plugin'] = 'RuboCop::DatabaseValidations::Plugin'
+
   spec.add_dependency 'activerecord', '>= 7.2.0'
+  spec.add_dependency 'lint_roller'
 
   spec.add_development_dependency 'benchmark-ips'
   spec.add_development_dependency 'bundler'

lib/rubocop-database_validations.rb

@@ -0,0 +1,4 @@
+require 'rubocop'
+
+require_relative 'rubocop/database_validations'
+require_relative 'rubocop/database_validations/plugin'

lib/rubocop/database_validations.rb

@@ -0,0 +1,2 @@
+require_relative '../../lib/database_validations/rubocop/cop/belongs_to'
+require_relative '../../lib/database_validations/rubocop/cop/uniqueness_of'

lib/rubocop/database_validations/plugin.rb

@@ -0,0 +1,28 @@
+require 'lint_roller'
+
+module RuboCop
+  module DatabaseValidations
+    class Plugin < LintRoller::Plugin
+      def about
+        LintRoller::About.new(
+          name: 'rubocop-database_validations',
+          version: ::DatabaseValidations::VERSION,
+          homepage: 'https://github.com/toptal/database_validations',
+          description: 'RuboCop cops for database_validations gem.'
+        )
+      end
+
+      def supported?(context)
+        context.engine == :rubocop
+      end
+
+      def rules(context)
+        LintRoller::Rules.new(
+          type: :path,
+          config_format: :rubocop,
+          value: File.join(__dir__, '..', '..', '..', 'config', 'rubocop-default.yml')
+        )
+      end
+    end
+  end
+end