diff --git a/README.md b/README.md
index 59aedc4..371a25d 100644
--- a/README.md
+++ b/README.md
@@ -1,29 +1,48 @@
 # Omniauth::Redmine
 
-TODO: Write a gem description
+Strategy to authenticate with Redmine via OAuth in Redmine.
+(https://github.com/suer/redmine_oauth_provider)
 
 ## Installation
 
+Build gem package:
+
+    $ rake build
+
+Unpack gem package in your application's root directory:
+
+    $ gem unpack some/directory/pkg/omniauth-redmine-X.Y.Z.gem
+
 Add this line to your application's Gemfile:
 
-    gem 'omniauth-redmine'
+    gem 'omniauth-redmine', :path => 'omniauth-redmine-X.Y.Z'
 
 And then execute:
 
-    $ bundle
+    $ bundle install --path .bundle
 
 Or install it yourself as:
 
-    $ gem install omniauth-redmine
+    $ gem install pkg/omniauth-redmine-X.Y.Z.gem
 
 ## Usage
 
-TODO: Write usage instructions here
+Here's an example, adding the middleware to a Rails app in config/initializers/omniauth.rb:
+
+    Rails.application.config.middleware.use OmniAuth::Builder do
+      provider :redmine, "consumer key", "consumer secret", :redmine_base_url => "http://redmine.base.url/"
+    end
+
+If you use devise, add this lines in config/initializers/devise.rb
+
+    config.omniauth :redmine, "consumer key", "consumer secret", :redmine_base_url => "http://redmine.base.url/"
+
+## License
+The MIT License (MIT)
+Copyright (c) 2013 suer
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
-## Contributing
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 
-1. Fork it
-2. Create your feature branch (`git checkout -b my-new-feature`)
-3. Commit your changes (`git commit -am 'Add some feature'`)
-4. Push to the branch (`git push origin my-new-feature`)
-5. Create new Pull Request
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/lib/omniauth-redmine.rb b/lib/omniauth-redmine.rb
new file mode 100644
index 0000000..81cacf6
--- /dev/null
+++ b/lib/omniauth-redmine.rb
@@ -0,0 +1 @@
+require 'omniauth/redmine'
diff --git a/lib/omniauth/redmine.rb b/lib/omniauth/redmine.rb
index 9d760fc..91a830b 100644
--- a/lib/omniauth/redmine.rb
+++ b/lib/omniauth/redmine.rb
@@ -1,7 +1 @@
-require "omniauth/redmine/version"
-
-module Omniauth
-  module Redmine
-    # Your code goes here...
-  end
-end
+require 'omniauth/strategies/redmine'
diff --git a/lib/omniauth/strategies/redmine.rb b/lib/omniauth/strategies/redmine.rb
new file mode 100644
index 0000000..fd5380b
--- /dev/null
+++ b/lib/omniauth/strategies/redmine.rb
@@ -0,0 +1,37 @@
+require 'omniauth/strategies/oauth'
+
+module OmniAuth
+  module Strategies
+    class Redmine < OmniAuth::Strategies::OAuth
+
+      def consumer
+        options.client_options = {
+          :authorize_url => "#{redmine_base_url}oauth/authorize",
+          :request_token_url => "#{redmine_base_url}oauth/request_token",
+          :access_token_url => "#{redmine_base_url}oauth/access_token"
+        }
+        super
+      end
+
+      uid { raw_info['user']['id'] }
+
+      info do
+        {
+          'nickname' => raw_info['user']['mail'],
+          'email' => raw_info['user']['mail'],
+          'name' => "#{raw_info['user']['lastname']} #{raw_info['user']['firstname']}"
+        }
+      end
+
+      def raw_info
+        @raw_info ||= MultiJson.decode(access_token.get("#{redmine_base_url}oauth/user_info.json").body)
+      end
+
+      private
+      def redmine_base_url
+        options.redmine_base_url << '/' unless options.redmine_base_url.end_with?('/')
+        options.redmine_base_url
+      end
+    end
+  end
+end
diff --git a/omniauth-redmine.gemspec b/omniauth-redmine.gemspec
index d2198b9..aaf47a2 100644
--- a/omniauth-redmine.gemspec
+++ b/omniauth-redmine.gemspec
@@ -4,12 +4,14 @@ $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require 'omniauth/redmine/version'
 
 Gem::Specification.new do |spec|
+  spec.add_dependency 'omniauth', '~> 1.1'
+
   spec.name          = "omniauth-redmine"
   spec.version       = Omniauth::Redmine::VERSION
   spec.authors       = ["suer"]
   spec.email         = ["suetsugu.r@gmail.com"]
-  spec.description   = %q{TODO: Write a gem description}
-  spec.summary       = %q{TODO: Write a gem summary}
+  spec.description   = %q{An OmniAuth strategy for Redmine}
+  spec.summary       = %q{An OmniAuth strategy for Redmine}
   spec.homepage      = ""
   spec.license       = "MIT"
 
@@ -18,6 +20,9 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
+  spec.add_runtime_dependency 'omniauth-oauth'
+  spec.add_runtime_dependency 'multi_json'
+
   spec.add_development_dependency "bundler", "~> 1.3"
   spec.add_development_dependency "rake"
 end