added Event and Location models in calendar app

widget_princessgabi/widget_calendar/models.py

 from django.db import models
 
 # Create your models here.
+class Location(models.Model):
+    LOCATION_CHOICES = (
+        ('onsite', 'Onsite'),
+        ('online', 'Online'),
+        ('hybrid', 'Hybrid'),
+    )
+
+    mode = models.CharField(max_length = 10, choices = LOCATION_CHOICES)
+    venue = models.TextField(null = True, blank = True)
+
+    def __str__(self):
+        return self.venue
+
+class Event(models.Model):
+    target_datetime = models.DateTimeField('target date')
+    activity = models.TextField()
+    estimated_hours = models.FloatField() 
+    location = models.ForeignKey(Location, on_delete = models.CASCADE)
+    course = models.ForeignKey(Course, on_delete = models.CASCADE)
+
+    def __str__(self):
+        return self.activity
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