Added build stage to gitlab-ci and fixed test-fail in User/tests

.gitlab-ci.yml

@@ -5,6 +5,15 @@ stages:
   - test
   - deploy
 
+build:
+  image: python:3.8.5-slim
+  before_script:
+    - apt-get clean
+    - pip install -r backend/secfit/requirements.txt
+  script:
+    - cd backend/secfit
+    - python manage.py runserver
+
 test-backend:
   stage: test
   image: python:3.8.5-slim

backend/secfit/users/tests/UserSerializer.py

 from django.test import TestCase
-from backend.secfit.users.serializers import UserSerializer
+from users.serializers import UserSerializer
 from django.contrib.auth import get_user_model
-from rest_framework import serializers
 
 class UserSerializerTestCase(TestCase):