diff --git a/src/sherlock/models.py b/src/sherlock/models.py
index 582d674..5a60a82 100644
--- a/src/sherlock/models.py
+++ b/src/sherlock/models.py
@@ -19,7 +19,15 @@ class Gauge(models.Model):
 class Diff(object):
     def __init__(self, mesure_1, mesure_2):
         self.increase = abs(mesure_1.diff(mesure_2))
-        self.delta = abs(mesure_1.moment - mesure_2.moment)
+        self.timedelta = abs(mesure_1.moment - mesure_2.moment)
+
+class MesureManager(models.Manager):
+    def create(self, moment, value, gauge_sn, category_label):
+        category, cat_created = Category.objects.get_or_create(name=category_label)
+        gauge, gauge_created = Gauge.objects.get_or_create(serial_number=gauge_sn, category=category)
+        mesure = Mesure.objects.create(moment=moment, value=value, gauge=gauge)
+
+        return mesure
 
 class Mesure(models.Model):
     moment = models.DateTimeField()
diff --git a/src/sherlock/tests.py b/src/sherlock/tests.py
index 7a86deb..a47e405 100644
--- a/src/sherlock/tests.py
+++ b/src/sherlock/tests.py
@@ -43,6 +43,10 @@ class TestGaugeModel(TestCase):
 
         self.assertEqual(1, len(gauge_1.mesures.all()))
 
+class TestMesureManager(TestCase):
+    def test_create(self):
+        raise Exception('not implemented yet')
+
 class TestMesureModel(TestCase):
 
     def setUp(self):