diff --git a/CHANGELOG.md b/CHANGELOG.md
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+++ b/CHANGELOG.md
@@ -0,0 +1,4 @@
+0.0.1
+-----
+
+- First release.
diff --git a/README.md b/README.md
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+++ b/README.md
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+# RuCaptcha
+
+
+This is a Captcha gem for Rails Application. It base on [mini_magick](https://github.com/minimagick/minimagick) to run ImageMagick command to draw Captcha image.
+
+So it's NO performance issue, and memory leak issue.
+
+Idea by: https://ruby-china.org/topics/20558#reply4
+
+### Requirements
+
+- ImageMagick
+- [mini_magick](https://github.com/minimagick/minimagick)
+
+### Usage
+
+Put rucaptcha in your `Gemfile`:
+
+```
+gem 'rucaptcha'
+```
+
+Create `config/initializes/rucaptcha.rb`
+
+```rb
+RuCaptcha.configure do
+  # Number of chars, default: 4
+  self.len = 4
+  # Image width, default: 180
+  self.width = 180
+  # Image height, default: 48
+  self.height = 48
+  # Font size, default: 38
+  self.font_size = 38
+end
+```
+
+Controller `app/controller/account_controller.rb`
+
+```rb
+class AccountController < ApplicationController
+  def create
+    @user = User.new(params[:user])
+    if verify_rucaptcha?(@user) && @user.save
+      redirect_to root_path, notice: 'Sign up successed.'
+    else
+      render 'account/new'
+    end
+  end
+end
+```
+
+View `app/views/account/new.html.erb`
+
+```erb
+<form>
+  ...
+  <div class="form-group">
+    <%= rucaptcha_input_tag(class: 'form-control', placeholder: 'Input Captcha') %>
+    <%= rucaptcha_image_tag(alt: 'Captcha') %>
+  </div>
+  ...
+</form>
+```
+
diff --git a/app/controllers/ru_captcha/captcha_controller.rb b/app/controllers/ru_captcha/captcha_controller.rb
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+++ b/app/controllers/ru_captcha/captcha_controller.rb
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+module RuCaptcha
+  class CaptchaController < ActionController::Base
+    def index
+      headers['Cache-Control'] = 'no-cache, no-store, max-age=0, must-revalidate'
+      headers['Pragma'] = 'no-cache'
+
+      send_data generate_rucaptcha, disposition: 'inline', type: 'image/png'
+    end
+  end
+
+end
diff --git a/config/routes.rb b/config/routes.rb
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+++ b/config/routes.rb
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+RuCaptcha::Engine.routes.draw do
+  root to: 'captcha#index'
+end
diff --git a/lib/rucaptcha.rb b/lib/rucaptcha.rb
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--- /dev/null
+++ b/lib/rucaptcha.rb
@@ -0,0 +1,28 @@
+require 'active_support/core_ext'
+require_relative 'rucaptcha/version'
+require_relative 'rucaptcha/configuration'
+require_relative 'rucaptcha/controller_helpers'
+require_relative 'rucaptcha/view_helpers'
+require_relative 'rucaptcha/engine'
+
+module RuCaptcha
+  class << self
+    def config
+      return @config if defined?(@config)
+      @config = Configuration.new
+      @config.len = 4
+      @config.width = 180
+      @config.height = 48
+      @config.font_size = 38
+      @config
+    end
+
+    def configure(&block)
+      config.instance_exec(&block)
+    end
+  end
+end
+
+
+ActionController::Base.send :include, RuCaptcha::ControllerHelpers
+ActionView::Base.send :include, RuCaptcha::ViewHelpers
diff --git a/lib/rucaptcha/captcha.rb b/lib/rucaptcha/captcha.rb
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+++ b/lib/rucaptcha/captcha.rb
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+require 'posix-spawn'
+
+module RuCaptcha
+  class Captcha
+    class << self
+      def create(code)
+        color = "rgba(#{rand(100)},#{rand(100)},#{rand(100)}, 1)"
+        size = "#{RuCaptcha.config.width}x#{RuCaptcha.config.height}"
+        command = <<-CODE
+          convert -size #{size} -fill "#{color}" -background white \
+          -draw 'stroke #{color} line #{rand(20)},#{rand(28)} #{rand(30) + 10},#{rand(48)}' \
+          -draw 'stroke #{color} line #{rand(50)},#{rand(28)} #{rand(180)},#{rand(48)}' \
+          -wave #{2 + rand(2)}x#{80 + rand(20)} \
+          -gravity Center -sketch 2x19+#{rand(6)} -pointsize #{RuCaptcha.config.font_size} -implode 0.3 label:#{code.upcase} png:-
+        CODE
+        command.strip!
+        # puts command
+        pid, stdin, stdout, stderr = POSIX::Spawn.popen4(command)
+        Process.waitpid(pid)
+        stdout.read
+      end
+    end
+  end
+end
diff --git a/lib/rucaptcha/configuration.rb b/lib/rucaptcha/configuration.rb
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+++ b/lib/rucaptcha/configuration.rb
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+module RuCaptcha
+  class Configuration
+    attr_accessor :width, :height, :font_size, :len
+  end
+end
diff --git a/lib/rucaptcha/controller_helpers.rb b/lib/rucaptcha/controller_helpers.rb
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--- /dev/null
+++ b/lib/rucaptcha/controller_helpers.rb
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+module RuCaptcha
+  module ControllerHelpers
+    extend ActiveSupport::Concern
+
+    included do
+      helper_method :verify_rucaptcha?
+    end
+
+    def generate_rucaptcha
+      session[:_rucaptcha] = SecureRandom.hex(RuCaptcha.config.len / 2)
+      return Captcha.create(session[:_rucaptcha])
+    end
+
+    def verify_rucaptcha?(resource = nil)
+      right = params[:_rucaptcha].strip == session[:_rucaptcha]
+      if resource && resource.respond_to?(:errors)
+        resource.errors.add('rucaptcha', 'invalid') unless right
+      end
+      right
+    end
+  end
+end
diff --git a/lib/rucaptcha/engine.rb b/lib/rucaptcha/engine.rb
new file mode 100644
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--- /dev/null
+++ b/lib/rucaptcha/engine.rb
@@ -0,0 +1,5 @@
+module RuCaptcha
+  class Engine < ::Rails::Engine
+    isolate_namespace RuCaptcha
+  end
+end
diff --git a/lib/rucaptcha/version.rb b/lib/rucaptcha/version.rb
new file mode 100644
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--- /dev/null
+++ b/lib/rucaptcha/version.rb
@@ -0,0 +1,4 @@
+module RuCaptcha
+  VERSION = '0.0.1'
+end
+
diff --git a/lib/rucaptcha/view_helpers.rb b/lib/rucaptcha/view_helpers.rb
new file mode 100644
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--- /dev/null
+++ b/lib/rucaptcha/view_helpers.rb
@@ -0,0 +1,13 @@
+module RuCaptcha
+  module ViewHelpers
+    def rucaptcha_input_tag(opts = {})
+      opts[:name] = '_rucaptcha'
+      tag(:input, opts)
+    end
+
+    def rucaptcha_image_tag(opts = {})
+      opts[:class] = opts[:class] || 'rucaptcha-image'
+      image_tag(ru_captcha.root_path, opts)
+    end
+  end
+end
diff --git a/rucaptcha.gemspec b/rucaptcha.gemspec
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+++ b/rucaptcha.gemspec
@@ -0,0 +1,21 @@
+lib = File.expand_path('../lib/', __FILE__)
+$:.unshift lib unless $:.include?(lib)
+
+require "rucaptcha/version"
+
+Gem::Specification.new do |s|
+  s.name = 'rucaptcha'
+  s.version = RuCaptcha::VERSION
+  s.authors = ['Jason Lee']
+  s.email = 'huacnlee@gmail.com'
+  s.files        = Dir.glob("lib/**/*") + Dir.glob("app/**/*") + Dir.glob("config/**/*") + %w(README.md CHANGELOG.md)
+  s.homepage = 'https://github.com/huacnlee/rucaptcha'
+  s.require_paths = ['lib']
+  s.summary = 'Captcha gem for Rails Application. It base on mini_magick to run ImageMagick command to draw Captcha image.'
+
+  s.add_dependency 'mini_magick', '>= 4.0.0'
+  s.add_dependency 'posix-spawn', '>= 0.3.0'
+
+  s.add_development_dependency 'rake'
+  s.add_development_dependency 'rspec', '>= 3.3.0'
+end