Move apps in main directory

Signed-off-by: Emmy D'Anello <emmy.danello@animath.fr>

api/serializers.py

@@ -0,0 +1,19 @@
+# Copyright (C) 2020 by Animath
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+from django.contrib.auth.models import User
+from rest_framework import serializers
+
+
+class UserSerializer(serializers.ModelSerializer):
+    """
+    Serialize a User object into JSON.
+    """
+    class Meta:
+        model = User
+        exclude = (
+            'username',
+            'password',
+            'groups',
+            'user_permissions',
+        )