Add tests on contact models

picampaign/contact/tests.py

 from django.test import TestCase
 
-# Create your tests here.
+from picampaign.contact.models import Contact
+
+class ContactMethodsTest(TestCase):
+    def test_full_name(self):
+        contact = Contact(first_name='Victor', last_name='Hugo')
+        self.assertEqual(contact.full_name(), 'Victor Hugo')
+