README.md in hydra-derivatives-0.0.1 vs README.md in hydra-derivatives-0.0.2

@@ -1,4 +1,36 @@
 hydra-derivatives
 =================
 
 Derivative generation for hydra
+
+If you have an ActiveFedora class like this:
+```ruby
+    class GenericFile < ActiveFedora::Base
+        include Hydra::Derivatives
+        
+        has_file_datastream :content
+        attr_accessor :mime_type
+
+        makes_derivatives_of :content, when: :mime_type, is_one_of: ['image/tiff', 'image/jpeg],
+             derivatives: { :thumbnail => {size: "200x150>", datastream: 'thumbnail'} }
+        makes_derivatives_of :content, when: :mime_type, is: 'application/pdf',
+             derivatives: { :thumbnail => {size: "338x493", datastream: 'thumbnail'} }
+        makes_derivatives_of :content, when: :mime_type, is_one_of: ['video/mpeg', 'video/avi'],
+             derivatives: { :webm => {format: "webm", datastream: 'webm'}, :mp4 => {format: "mp4", datastream: 'mp4'} }, processors: :video
+        makes_derivatives_of :content, when: :mime_type, is_one_of: ['audio/wav', 'audio/mpeg'],
+             derivatives: {  :mp3 => {format: 'mp3', datastream: 'mp3'}, :ogg => {format: 'ogg', datastream: 'ogg'} }, processors: :audio
+    end
+```
+
+And you add some content to it:
+
+```ruby
+   obj = GenericFile.new
+   obj.content.content = File.open(...)
+   obj.mime_type = 'image/tiff'
+   obj.save
+```
+
+Then when you call `obj.create_derivatives` a new datastream, called 'thumbnail' will have been created, with a downsized image in it.
+
+We recommend you run `obj.create_derivatives` in a background worker, because some derivative creation (especially videos) can take a long time.