Added usage in README

README.md

@@ -7,12 +7,48 @@ When IBAN validation is not enough.
 [![Dependency Status](https://www.versioneye.com/user/projects/59d393190fb24f0046190d85/badge.svg?style=flat-square)](https://www.versioneye.com/user/projects/59d393190fb24f0046190d85?style=flat)
 
 ## Features
-* IBAN validation (`ActiveModel::EachValidator` and control digits calculator function)
+* IBAN validation (`ActiveModel::EachValidator` and control digits calculator function).
 * National account digits control validation (currently only ES included, others countries can be added).
-* BICs mapping from IBAN bank code part: COUNTRY + BANK => BIC code
+* Associated tags to countries (currently only SEPA tag is available).
+* BICs mapping from IBAN bank code part: COUNTRY + BANK => BIC code.
   * Currently, static data only includes some ES banks, PRs are welcomed.
 * Optional database model to allow apps to dynamically add new BICs mapping.
 
+## Usage
+
+1. Validator: add IBAN validation to your models.
+
+```ruby
+validates :iban, iban: true
+```
+
+You can also validate that IBAN is from a SEPA country.
+
+```ruby
+validates :iban, iban: { tags: [:sepa] }
+```
+
+2. IBAN control digits calculation
+
+```ruby
+2.4.1 :001 > IbanBic.calculate_check("ES0000030000300000000000")
+ => 87
+```
+
+3. IBAN parsing
+
+```ruby
+2.4.1 :001 > IbanBic.parse("ES8700030000300000000000")
+=> {"country"=>"ES", "iban_check"=>"87", "bank"=>"0003", "branch"=>"0000", "check"=>"30", "account"=>"0000000000"}
+```
+
+4. BIC calculation (bank code must be in the static file or in the database)
+
+```ruby
+2.4.1 :009 > IbanBic.calculate_bic("ES8700030000300000000000")
+ => "BDEPESM1XXX"
+```
+
 ## Installation
 
 1. Add this line to your application's Gemfile
@@ -29,7 +65,7 @@ $ bundle
 
 3. Run installer 
 
-3.1. Using BICs dynamic data from database
+3.a. Using BICs dynamic data from database
 
 Add a `bics` table to your database and an initializer file for configuration:
 
@@ -44,7 +80,7 @@ Load static data to the created `bics` table:
 $ bundle exec rake iban_bic:load_data
 ```
 
-3.2. Using static data from YAML files
+3.b. Using static data from YAML files
 
 Create an initializer file for configuration: