README.md in ddplugin-1.0.1 vs README.md in ddplugin-1.0.2

@@ -1,9 +1,10 @@
-[![Build Status](https://travis-ci.org/ddfreyne/ddplugin.png)](https://travis-ci.org/ddfreyne/ddplugin)
-[![Code Climate](https://codeclimate.com/github/ddfreyne/ddplugin.png)](https://codeclimate.com/github/ddfreyne/ddplugin)
-[![Coverage Status](https://coveralls.io/repos/ddfreyne/ddplugin/badge.png?branch=master)](https://coveralls.io/r/ddfreyne/ddplugin)
-[![Inline docs](http://inch-ci.org/github/ddfreyne/ddplugin.png)](http://inch-ci.org/github/ddfreyne/ddplugin)
+[![Gem version](http://img.shields.io/gem/v/ddplugin.svg)](http://rubygems.org/gems/ddplugin)
+[![Gem downloads](https://img.shields.io/gem/dt/ddplugin.svg)](http://rubygems.org/gems/ddplugin)
+[![Build status](http://img.shields.io/travis/ddfreyne/ddplugin.svg)](https://travis-ci.org/ddfreyne/ddplugin)
+[![Code Climate](http://img.shields.io/codeclimate/github/ddfreyne/ddplugin.svg)](https://codeclimate.com/github/ddfreyne/ddplugin)
+[![Code Coverage](https://img.shields.io/coveralls/ddfreyne/ddplugin.svg)](https://coveralls.io/r/ddfreyne/ddplugin)
 
 # ddplugin
 
 *ddplugin* is a library for managing plugins.
 
@@ -27,11 +28,11 @@
 
 A typical way to use plugins would be to store the plugin names in a configuration file, so that the actual plugin implementations can be discovered at runtime.
 
 ## Requirements
 
-*ddplugin* requires Ruby 2.1 or higher.
+*ddplugin* requires Ruby 2.3 or higher.
 
 ## Versioning
 
 *ddplugin* adheres to [Semantic Versioning 2.0.0](http://semver.org).
 
@@ -61,72 +62,105 @@
 class DataSource
   extend DDPlugin::Plugin
 end
 ```
 
-To define a plugin, create a class that inherits from the plugin type and sets the identifier:
+To define a plugin, create a class that inherits from the plugin type and sets the identifier, either as a symbol or a string:
 
 ```ruby
 class ERBFilter < Filter
+  # Specify the identifier as a symbol…
   identifier :erb
 end
 
 class HamlFilter < Filter
-  identifier :haml
+  # … or as a string …
+  identifier 'haml'
 end
 
 class FilesystemDataSource < DataSource
-  identifier :filesystem
+  # … or even provide multiple.
+  identifiers :filesystem, :file_system
 end
 
 class PostgresDataSource < DataSource
-  identifier :postgres
+  # … or mix and match (not sure why you would, though)
+  identifier :postgres, 'postgresql'
 end
 ```
 
 To find a plugin of a given type and with a given identifier, call `.named` on the plugin type, passing an identifier:
 
 ```ruby
 Filter.named(:erb)
 # => ERBFilter
 
-Filter.named(:haml)
+Filter.named('haml')
 # => HamlFilter
 
 DataSource.named(:filesystem)
 # => FilesystemDataSource
 
 DataSource.named(:postgres)
 # => PostgresDataSource
 ```
 
+In a real-world situation, the plugin types could be described in the environment:
+
+```
+% cat .env
+DATA_SOURCE_TYPE=postgres
+```
+
+```ruby
+DataSource.named(ENV.fetch('DATA_SOURCE_TYPE'))
+# => PostgresDataSource
+```
+
+… or in a configuration file:
+
+```
+% cat config.yml
+data_source: 'filesystem'
+```
+
+```ruby
+config = YAML.load_file('config.yml')
+DataSource.named(config.fetch('data_source'))
+# => FilesystemDataSource
+```
+
 To get all plugins of a given type, call `.all` on the plugin type:
 
 ```ruby
 Filter.all
-# => [ ERBFilter, HamlFilter ]
+# => [ERBFilter, HamlFilter]
 
 DataSource.all
-# => [ FilesystemDataSource, PostgresDataSource ]
+# => [FilesystemDataSource, PostgresDataSource]
 ```
 
-To get the identifier of a plugin, call `.identifier`:
+To get the identifier of a plugin, call `.identifier`, which returns a symbol:
 
 ```ruby
 Filter.named(:erb).identifier
 # => :erb
 
+Filter.named('haml').identifier
+# => :haml
+
 PostgresDataSource.identifier
 # => :postgres
 ```
 
 ## Development
 
 Pull requests and issues are greatly appreciated.
 
 When you submit a pull request, make sure that your change is covered by tests, and that the `README` and [YARD](http://yardoc.org/) source code documentation are still up-to-date.
 
-To run the tests, execute `rake`:
+To run the tests:
 
 ```
-% rake
+% bundle install
+% bundle exec rake
 ```