Add OpenRouter integration

Author: khasinski

lib/ruby_llm.rb

@@ -15,7 +15,8 @@
   'llm' => 'LLM',
   'openai' => 'OpenAI',
   'api' => 'API',
-  'deepseek' => 'DeepSeek'
+  'deepseek' => 'DeepSeek',
+  'openrouter' => 'OpenRouter'
 )
 loader.setup
 
@@ -68,6 +69,7 @@ def logger
 RubyLLM::Provider.register :anthropic, RubyLLM::Providers::Anthropic
 RubyLLM::Provider.register :gemini, RubyLLM::Providers::Gemini
 RubyLLM::Provider.register :deepseek, RubyLLM::Providers::DeepSeek
+RubyLLM::Provider.register :openrouter, RubyLLM::Providers::OpenRouter
 
 if defined?(Rails::Railtie)
   require 'ruby_llm/railtie'

lib/ruby_llm/configuration.rb

@@ -14,6 +14,7 @@ class Configuration
                   :anthropic_api_key,
                   :gemini_api_key,
                   :deepseek_api_key,
+                  :openrouter_api_key,
                   :default_model,
                   :default_embedding_model,
                   :default_image_model,