add docstrings&updated docs

docs/class_based_views.md

@@ -28,7 +28,7 @@ class SimpleView(HTTPMethodView):
   def delete(self, request):
       return text('I am delete method')
 
-app.add_route(SimpleView(), '/')
+app.add_route(SimpleView.as_view(), '/')
 
 ```
 
@@ -40,6 +40,19 @@ class NameView(HTTPMethodView):
   def get(self, request, name):
     return text('Hello {}'.format(name))
 
-app.add_route(NameView(), '/<name>')
+app.add_route(NameView.as_view(), '/<name>')
+
+```
+
+If you want to add decorator for class, you could set decorators variable
+
+```
+class ViewWithDecorator(HTTPMethodView):
+  decorators = (some_decorator_here)
+
+  def get(self, request, name):
+    return text('Hello I have a decorator')
+
+app.add_route(ViewWithDecorator.as_view(), '/url')
 
 ```

sanic/views.py

@@ -7,7 +7,7 @@ class HTTPMethodView:
     to every HTTP method you want to support.
 
     For example:
-        class DummyView(View):
+        class DummyView(HTTPMethodView):
 
             def get(self, request, *args, **kwargs):
                 return text('I am get method')
@@ -20,16 +20,16 @@ class HTTPMethodView:
     405 response.
 
     If you need any url params just mention them in method definition:
-        class DummyView(View):
+        class DummyView(HTTPMethodView):
 
             def get(self, request, my_param_here, *args, **kwargs):
                 return text('I am get method with %s' % my_param_here)
 
     To add the view into the routing you could use
-        1) app.add_route(DummyView(), '/')
+        1) app.add_route(DummyView.as_view(), '/')
-        2) app.route('/')(DummyView())
+        2) app.route('/')(DummyView.as_view())
 
-    TODO: add doc about devorators
+    To add any decorator you could set it into decorators variable
     """
 
     decorators = ()
@@ -44,7 +44,8 @@ class HTTPMethodView:
 
     @classmethod
     def as_view(cls, *class_args, **class_kwargs):
-        """ TODO: add docs
+        """ Converts the class into an actual view function that can be used
+        with the routing system.
 
         """
         def view(*args, **kwargs):