Fix wrong user type check on domain model.

taiga/base/domains/models.py

@@ -47,13 +47,13 @@ class Domain(models.Model):
         return self.domain
 
     def user_is_owner(self, user):
-        return self.members.filter(id=user.id, is_owner=True).count() > 0
+        return self.members.filter(user_id=user.id, is_owner=True).exists()
 
     def user_is_staff(self, user):
-        return self.members.filter(id=user.id, is_staff=True).count() > 0
+        return self.members.filter(user_id=user.id, is_staff=True).exists()
 
     def user_is_normal_user(self, user):
-        return self.members.filter(id=user.id, is_owner=False, is_staff=False).count() > 0
+        return self.members.filter(user_id=user.id, is_owner=False, is_staff=False).exists()
 
 
 class DomainMember(models.Model):

taiga/base/domains/serializers.py

@@ -1,9 +1,10 @@
 # -*- coding: utf-8 -*-
 
 from rest_framework import serializers
-from .models import Domain, DomainMember
 from taiga.base.users.serializers import UserSerializer
 
+from .models import Domain, DomainMember
+
 
 class DomainSerializer(serializers.ModelSerializer):
     projects = serializers.SerializerMethodField('get_projects')
@@ -18,5 +19,6 @@ class DomainSerializer(serializers.ModelSerializer):
 
 class DomainMemberSerializer(serializers.ModelSerializer):
     user = UserSerializer()
+
     class Meta:
         model = DomainMember