Set ruby code in readme to be highlighted on github

README.md

@@ -12,7 +12,9 @@ Installation
 
 The usual stuff. Either
 
-    gem 'jerry'
+```ruby
+gem 'jerry'
+```
 
 then
 
@@ -27,37 +29,45 @@ Usage
 
 Let's say you have the following code:
 
-    class Window; end
-    class Door; end
-
-    class House
-      attr_reader :window, :door
-      
-      def initialize(window, door)
-        @window = window
-        @door = door
-      end
-    end
+```ruby
+class Window; end
+class Door; end
+
+class House
+  attr_reader :window, :door
+
+  def initialize(window, door)
+    @window = window
+    @door = door
+  end
+end
+```
 
 First, require jerry:
 
-    require 'jerry'
+```ruby
+require 'jerry'
+```
 
 Then, define a config class. This class tells jerry how to construct your application.
 
-    class MyConfig < Jerry::Config
-      component(:window) { Window.new }
-      component(:door) { Door.new }
-      component(:house) { House.new rig(:window), rig(:door) }
-    end
+```ruby
+class MyConfig < Jerry::Config
+  component(:window) { Window.new }
+  component(:door) { Door.new }
+  component(:house) { House.new rig(:window), rig(:door) }
+end
+```
 
 The `component` method defines a component. Usually you'll want a component per class. The `rig` method tells jerry to
 build a component.
 
 Finally, when you want to build your application, ask jerry to do it for you.
 
-    jerry = Jerry.new MyConfig.new
-    house = jerry.rig :house
+```ruby
+jerry = Jerry.new MyConfig.new
+house = jerry.rig :house
+```
 
 Scopes
 ------
@@ -66,21 +76,23 @@ The `component` method lets you specify a scope. The scope can either be `:singl
 `:single`. If you set the scope to `:single` only one instance of the component will be created. If you set it to
 `:instance`, a new instance of the component will be created each time you call `rig`.
 
-    class MyConfig < Jerry::Config
-      component(:window, scope: :instance) { Window.new }
-      component(:door, scope: :single) { Door.new }
-    end
-    jerry = Jerry.new MyConfig.new
-
-    window_a = jerry.rig :window
-    window_b = jerry.rig :window
-    window_a.object_id == window_b.object_id
-    #=> false
-
-    door_a = jerry.rig :door
-    door_b = jerry.rig :door
-    door_a.object_id == door_b.object_id
-    #=> true
+```ruby
+class MyConfig < Jerry::Config
+  component(:window, scope: :instance) { Window.new }
+  component(:door, scope: :single) { Door.new }
+end
+jerry = Jerry.new MyConfig.new
+
+window_a = jerry.rig :window
+window_b = jerry.rig :window
+window_a.object_id == window_b.object_id
+#=> false
+
+door_a = jerry.rig :door
+door_b = jerry.rig :door
+door_a.object_id == door_b.object_id
+#=> true
+```
 
 Multiple configs
 ----------------
@@ -91,13 +103,15 @@ configs to `Jerry.new` or you can use `jerry << SomeConfig.new` to add configs t
 If two configs define the same component, the config that was inserted last will have priority. With `Jerry.new`, the
 later arguments have priority.
 
-    class ConfA < Jerry::Config
-      component(:thing) { "from a" }
-    end
-    class ConfB < Jerry::Config
-      component(:thing) { "from b" }
-    end
-    jerry = Jerry.new ConfA.new, ConfB.new
-
-    jerry.rig :thing
-    #=> "from b"
+```ruby
+class ConfA < Jerry::Config
+  component(:thing) { "from a" }
+end
+class ConfB < Jerry::Config
+  component(:thing) { "from b" }
+end
+jerry = Jerry.new ConfA.new, ConfB.new
+
+jerry.rig :thing
+#=> "from b"
+```