README.md in config-factory-0.0.6 vs README.md in config-factory-0.0.7

@@ -9,10 +9,20 @@
 [Abstract Factory](https://web.archive.org/web/20111109224959/http://www.informit.com/articles/article.aspx?p=1398599),
 pattern, with run-time configuration provided by hashes or YAML files.
 
 ## Example
 
+The abstract configuration factory declares a `key`, which is used to look up the concrete
+config class for a given configuration. Concrete implementations register themselves with a
+DSL method named after the `key` value.
+
+In the example below, the `SourceConfig` abstract factory declares the key `:protocol`; the
+concrete classes `OAISourceConfig` and `ResyncSourceConfig` register themselves with
+`protocol: 'OAI'` and `protocol: 'Resync'`, respectively. `SourceConfig.for_environment()`
+will then look for a `protocol:` line in the configuration file to determine which
+registered concrete class to instantiate.
+
 ```ruby
 class SourceConfig
   include Config::Factory
   key :protocol
 end
@@ -80,6 +90,41 @@
 # => {:test=>#<Config::Factory::Environment:0x007fe8d3863dc8 @name=:test, @configs={"source"=>{"protocol"=>"Resync", "capability_list_url"=>"http://localhost:8888/capabilitylist.xml"}}>, :production=>#<Config::Factory::Environment:0x007fe8d3863be8 @name=:production, @configs={"source"=>{"protocol"=>"OAI", "oai_base_url"=>"http://oai.example.org/oai", "metadata_prefix"=>"some_prefix", "set"=>"some_set", "seconds_granularity"=>true}}>} 
 test_env = environments[:test]
 # => #<Config::Factory::Environment:0x007fe8d383a400 @name=:test, @configs={"source"=>{"protocol"=>"Resync", "capability_list_url"=>"http://localhost:8888/capabilitylist.xml"}}> 
 source_config = SourceConfig.for_environment(test_env, :source)
 # => #<ResyncSourceConfig:0x007fe8d48180c0 @capability_list_url="http://localhost:8888/capabilitylist.xml"> 
+```
+
+## Config classes with only one implementation
+
+`config-factory` also supports instantiating concrete configuration classes directly.
+In this case, we simply don't declare a `key` for the class, and the configuration hash
+will be passed directly to the initializer of the concrete class.
+
+```ruby
+class DBConfig
+  include Config::Factory
+
+  def initialize(connection_info)
+    @connection_info = connection_info
+  end
+end
+```
+
+```YAML
+test:
+  db:
+    adapter: sqlite3
+    database: ':memory:'
+    pool: 5
+    timeout: 5000
+
+production:
+  db:
+    adapter: mysql2
+    host: mydb.example.org
+    database: myapp
+    username: myuser
+    password: blank
+    port: 3306
+    encoding: utf8
 ```