added company at module endpoint, allow null parent at departments

app/applicationlayer/management/department/serializer.py

 from rest_framework import serializers
-from app.entities.models import Department
+from app.entities.models import Department, Company
 
 
 class DepartmentSerializer(serializers.ModelSerializer):
+    def to_representation(self, instance):
+        company_name = Company.objects.filter(
+            id=instance.company.id
+        ).values().first()
+        ret = super().to_representation(instance)
+        ret['company'] = company_name
+        # ret['application'] = application_name
+
+        return ret
+        
     class Meta:
         model = Department
         fields = '__all__'

app/entities/migrations/0004_auto_20190910_1610.py

+# Generated by Django 2.2 on 2019-09-10 16:10
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('entities', '0003_auto_20190910_0956'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='module',
+            name='parent',
+            field=models.IntegerField(blank=True, null=True),
+        ),
+    ]

app/entities/models.py

@@ -57,7 +57,7 @@ class Module(AuditClass):
         blank=True,
         null=True
     )
-    parent = models.IntegerField()
+    parent = models.IntegerField(blank=True, null=True)
     sort_id = models.IntegerField()
     component = models.CharField(
         max_length=255,