Added asset model and basic views

asset/models.py

@@ -0,0 +1,18 @@
+from django.db import models
+from django.conf import settings
+from django.contrib.auth import get_user_model
+# from django.contrib.auth.models import User
+from container.models import Container
+
+def get_sentinel_user():
+    return get_user_model().objects.get_or_create(username='deleted')[0]
+
+class Asset(models.Model):
+    named_id = models.CharField(max_length=40, unique=True)
+    description = models.CharField(max_length=250, blank=True)
+    quantity = models.IntegerField(default=1)
+    created_ts = models.DateTimeField('datetime created', auto_now_add=True)
+    created_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.SET(get_sentinel_user), related_name='created_assets')
+    changed_ts = models.DateTimeField('datetime updated', auto_now=True)
+    changed_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.SET(get_sentinel_user), related_name='changed_assets')
+