add whole new app for balance prediction, replace uwsgi, update everything

core/models.py

@@ -0,0 +1,49 @@
+from decimal import Decimal
+
+from django.db import models
+from django.utils import timezone
+
+
+class PriceField(models.DecimalField):
+    # allowing numbers until 99,999.99
+    max_digits = 7
+    decimal_places = 2
+
+    def to_python(self, value):
+        value = super().to_python(value)
+        if isinstance(value, Decimal):
+            return value.quantize(Decimal(10) ** -self.decimal_places)
+        return value
+
+    def __init__(self, *args, **kwargs):
+        kwargs['max_digits'] = self.max_digits
+        kwargs['decimal_places'] = self.decimal_places
+        super().__init__(*args, **kwargs)
+
+
+class Subject(models.Model):
+    name = models.CharField(max_length=64)
+    created_time = models.DateTimeField(default=timezone.now)
+
+    def __str__(self):
+        return self.name
+
+
+class Transaction(models.Model):
+    class Meta:
+        get_latest_by = "booking_date"
+
+    amount = PriceField()
+    booking_date = models.DateField()
+    subject = models.ForeignKey(
+        to=Subject, on_delete=models.CASCADE,
+        related_name="transactions", related_query_name="transaction",
+    )
+
+
+class Balance(models.Model):
+    class Meta:
+        get_latest_by = "date"
+
+    amount = PriceField()
+    date = models.DateField()