README.md in przelewy24_payment-0.1.1 vs README.md in przelewy24_payment-0.1.2

@@ -1,25 +1,134 @@
 # Przelewy24Payment
 
-TODO: Write a gem description
+It's rails gem to integrate polish payment method: przelewy24.pl
 
 ## Installation
 
 Add this line to your application's Gemfile:
 
     gem 'przelewy24_payment'
 
 And then execute:
 
-    $ bundle
+    $ bundle install
 
 Or install it yourself as:
 
     $ gem install przelewy24_payment
 
+After this create przelewy24_payment config:
+
+    $ rails g przelewy24_payment:install
+
+And you can there "config/initializers/przelewy24_payment.rb" setup your settings:
+
+```ruby
+Przelewy24Payment.setup do |config|
+  config.seller_id = 'your_seller_id'
+  config.language = 'pl'
+  config.mode = :development
+  config.error_url = 'http://localhost:3000/your_payment/comeback'
+  config.comeback_url = 'http://localhost:3000/your_payment/comeback'
+end
+```
+
 ## Usage
 
-TODO: Write usage instructions here
+Your controller e.g 'PaymentController' should only include:
+
+```ruby
+class YourPaymentController < ApplicationController
+  include Przelewy24PaymentController
+  ...
+```
+
+And you should also have this methods in your payment controller:
+
+```ruby
+class YourPaymentController < ApplicationController
+  include Przelewy24PaymentController
+  ...
+
+  # after success payemnt this method will be trigger
+  def payment_success(payment_params)
+    # payment_params returns hash with:
+    # p24_session_id
+    # p24_order_id
+    # p24_kwota
+    # p24_karta
+    # p24_order_id_full
+    # p24_crc
+
+    # e.g
+    # payment = Payment.find_by_session_id(payment_params[:p24_session_id])
+  end
+
+  # after error payemnt this method will be trigger
+  def payment_error(payment_params, code, description)
+    # payment_params returns hash with:
+    # p24_session_id
+    # p24_order_id
+    # p24_kwota
+    # p24_error_code
+    # p24_order_id_full
+    # p24_crc
+    #
+    # code return error code
+    # description return error description
+  end
+
+  def payment_verify(response_params)
+    # e.g:
+    # payment = Payment.find_by_session_id(response_params[:p24_session_id])
+
+    # you must return hash with amount which was save in your db and optional if you use your crc_key
+    return data = { :amount => payment.value }
+
+    #or
+
+    # optional variant:
+    return data = { :amount => your_payment_value, :crc_key => your_crc_key }
+  end
+```
+
+Last step, on your payment view e.g 'app/views/YourController/your_payment.html.haml' you should add:
+
+```ruby
+= payment_button(@data)
+```
+
+And also on your payment controller you should specify @data hash e.g:
+
+```ruby
+class YourPaymentController < ApplicationController
+  include Przelewy24PaymentController
+  ...
+
+  def your_payment
+    session_id = Przelewy24Payment.friendly_token[0,20]
+    value = give_your_amount
+    @data = { :session_id =>  session_id,
+              :description => "opis",
+              :value => value,
+              :client => 'Adam Nowak',
+              :address => 'Powstancow 22/2',
+              :zipcode => '53-456',
+              :city => 'Wroclaw',
+              :country => 'Polska',
+              :email => '[e-mail]',
+              # adding this params, you overwrite your config settings so this param is optional
+              # :language => 'pl',
+              # :crc => your_crc_key,
+              # :seller_id => seller_id
+            }
+  end
+
+  ...
+
+```
+
+Finish :)
 
 ## Contributing
 
 1. Fork it
 2. Create your feature branch (`git checkout -b my-new-feature`)