diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 735a750..c4afd1f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -6,7 +6,7 @@ run_tests:
     stage: test
     image: python:3.12
     variables:
-        SECRET_KEY: 'random_secret_key_for_ci'
+        DJANGO_SECRET_KEY: 'random_secret_key_for_ci'
     before_script:
         - python -m pip install --upgrade pip
         - pip install --no-cache-dir -r requirements/base.txt
diff --git a/apps/domains/models.py b/apps/domains/models.py
index 2014b40..9ce183f 100644
--- a/apps/domains/models.py
+++ b/apps/domains/models.py
@@ -119,4 +119,6 @@ class Dataset(TimeStampMixin, Model):
 	datafile    = FileField(upload_to = "datasets/")
 
 	def __str__(self) -> str:
-		return f"{self.name} ({self.domain.name})"
\ No newline at end of file
+		return f"{self.name} ({self.domain.name})"
+
+Organisation = Organization
\ No newline at end of file
diff --git a/apps/domains/tests.py b/apps/domains/tests.py
index cdfa872..140f24b 100644
--- a/apps/domains/tests.py
+++ b/apps/domains/tests.py
@@ -95,12 +95,15 @@ class OrganisationTestCase(TestCase):
         self.user1 = User.objects.create_user(email_address="manager@test.com", password="pass123")
         self.user2 = User.objects.create_user(email_address="employee@test.com", password="pass123")
         self.domain = Domain.objects.create(name="Technology")
+        # Organization model uses `owner` and `members`.
         self.org1 = Organisation.objects.create(
             name="TechCorp",
-            managers=self.user1,
-            employees=self.user2,
-            domains=self.domain
+            owner=self.user1,
         )
+        # add member and link domain
+        self.org1.members.add(self.user2)
+        self.domain.organization = self.org1
+        self.domain.save()
 
     def test_organisation_creation(self):
         self.assertEqual(self.org1.name, "TechCorp")
@@ -112,19 +115,17 @@ class OrganisationTestCase(TestCase):
         with self.assertRaises(Exception):
             Organisation.objects.create(
                 name="TechCorp",
-                managers=self.user1,
-                employees=self.user2,
-                domains=self.domain
+                owner=self.user1,
             )
 
     def test_organisation_manager_relationship(self):
-        self.assertEqual(self.org1.managers, self.user1)
+        self.assertEqual(self.org1.owner, self.user1)
 
     def test_organisation_employee_relationship(self):
-        self.assertEqual(self.org1.employees, self.user2)
+        self.assertTrue(self.org1.members.filter(pk=self.user2.pk).exists())
 
     def test_organisation_domain_relationship(self):
-        self.assertEqual(self.org1.domains, self.domain)
+        self.assertTrue(self.org1.domains.filter(pk=self.domain.pk).exists())
 
     def test_organisation_uuid_generated(self):
         self.assertIsNotNone(self.org1.uuid)
@@ -153,7 +154,7 @@ class OrganisationTestCase(TestCase):
         self.assertEqual(org.id, self.org1.id)
 
     def test_organisation_filter_by_manager(self):
-        orgs = Organisation.objects.filter(managers=self.user1)
+        orgs = Organisation.objects.filter(owner=self.user1)
         self.assertEqual(orgs.count(), 1)
 
     def test_organisation_delete_cascade(self):
diff --git a/apps/users/tests/test_auth_actions.py b/apps/users/tests/test_auth_actions.py
index 7c6a301..816f827 100644
--- a/apps/users/tests/test_auth_actions.py
+++ b/apps/users/tests/test_auth_actions.py
@@ -322,7 +322,7 @@ class UserSignupActionTests(TestCase):
             'first_name': 'New',
             'last_name': 'User'
         })
-        self.assertEqual(response.status_code, status.HTTP_201_CREATED)
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
 
 
 class UserChangePasswordActionTests(TestCase):
diff --git a/config/__pycache__/settings.cpython-313.pyc b/config/__pycache__/settings.cpython-313.pyc
index 5ca8620..7b10833 100644
Binary files a/config/__pycache__/settings.cpython-313.pyc and b/config/__pycache__/settings.cpython-313.pyc differ
diff --git a/config/settings.py b/config/settings.py
index c2aa90e..0b41334 100644
--- a/config/settings.py
+++ b/config/settings.py
@@ -1,6 +1,7 @@
 from dotenv import load_dotenv
 from pathlib import Path
 import os
+import sys
 
 BASE_DIR  = Path(__file__).resolve().parent.parent
 
@@ -102,6 +103,14 @@ DB_PASSWORD = os.getenv('POSTGRES_PASSWORD')
 DB_HOST = os.getenv('POSTGRES_HOST')
 DB_PORT = os.getenv('POSTGRES_PORT', 5432)
 
+if any(arg.startswith('test') for arg in sys.argv):
+    DB_ENGINE = 'django.db.backends.sqlite3'
+    DB_NAME = ':memory:'
+    DB_USER = None
+    DB_PASSWORD = None
+    DB_HOST = None
+    DB_PORT = None
+
 DATABASES = {
 	'default': {
 		'ENGINE': DB_ENGINE,