README.md in duty_calculator-0.0.1 vs README.md in duty_calculator-0.0.2

@@ -19,10 +19,70 @@
 
     $ gem install duty_calculator
 
 ## Usage
 
-TODO: Write usage instructions here
+### Initializer
+
+If using rails you can create an initializer that sets the configuration for the client.
+
+```ruby
+DutyCalculator.configure do |config|
+  config.api_key = '###############'
+  # optional default overrides
+  config.api_root = 'http://something.com'
+  config.api_version = 'v3.0'
+  config.sandbox = true
+  config.debug = true
+end
+
+```
+
+### Listing Categories
+
+```ruby
+2.1.2 :008 > DutyCalculator::Category.list_all
+{
+  "categories"=>{
+    "category"=>{
+      "name"=>"Health & Beauty",
+      "id"=>"L1-84",
+      "subcategory"=>{
+        "name"=>"Bath & Shower",
+        "id"=>"L2-278",
+        "item"=>[
+          {
+            "id"=>"522",
+            "__content__"=>"Hydrotherapy Spa Bath"
+          },
+          ...
+        ]
+      }
+    }
+  }
+}
+```
+
+### Listing Currencies
+
+```ruby
+2.1.2 :009 > DutyCalculator::Currency.list_all
+ {
+   "currencies"=>{
+     "currency"=>[
+       {
+         "code"=>"EUR",
+         "__content__"=>"Euro "
+       },
+       {
+         "code"=>"GBP",
+         "__content__"=>"£ Sterling"
+       },
+       ...
+     ]
+   }
+ }
+```
 
 ## Contributing
 
 1. Fork it ( https://github.com/[my-github-username]/duty_calculator/fork )
 2. Create your feature branch (`git checkout -b my-new-feature`)