Merge pull request 'Close #13' (#19) from heinzel into master

Reviewed-on: #19

dav_registration/models.py

@@ -109,6 +109,8 @@ class Registration(models.Model):
         text = """{fullname}
 {address}, {postal_code} {city}
 
+DAV Mitgliedsnummer: {dav_number}
+
 Erfahrung:
 {experience}
 
@@ -120,6 +122,7 @@ Anmerkung:
             address=self.address,
             postal_code=self.postal_code,
             city=self.city,
+            dav_number=self.dav_number,
             experience=self.experience,
             note=self.note,
         )