Add Clacks Overhead header on each response. Closes #84

Signed-off-by: Yohann D'ANELLO <yohann.danello@gmail.com>

note_kfet/middlewares.py

@@ -142,3 +142,17 @@ class TurbolinksMiddleware(object):
                     location = request.session.pop('_turbolinks_redirect_to')
                     response['Turbolinks-Location'] = location
         return response
+
+
+class ClacksMiddleware(object):
+    """
+    Add Clacks Overhead header on each response.
+    See https://www.gnuterrypratchett.com/
+    """
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        response = self.get_response(request)
+        response['X-Clacks-Overhead'] = 'GNU Terry Pratchett'
+        return response