added simple model setup for django tweetbot;

backend/app_be/models.py

@@ -1,3 +1,15 @@
 from django.db import models
 
 # Create your models here.
+class User(models.Model):
+    ...
+
+class Tweet(models.Model):
+    user = models.ForeignKey(User, on_delete=models.CASCADE)
+
+class Feed(models.Model):
+    url = models.CharField(max_length=100)
+    active = models.BooleanField()
+
+class FeedEntry(models.Model):
+    tweeted = models.BooleanField()