Initial checkin

app/models/shift.py

@@ -0,0 +1,19 @@
+from app.extensions import db, ma
+from flask_marshmallow import fields
+
+class Shift(db.Model):
+    id = db.Column(db.Integer, primary_key=True)
+    battery_changes = db.relationship('BatteryChange', 
+                                      backref='battery_changes', 
+                                      order_by='BatteryChange.order')
+
+class ShiftSchema(ma.Schema):
+    battery_changes = ma.Nested('BatteryChangeSchema', many=True)
+    all_completed = fields.fields.Method('get_all_completed')
+    class Meta:
+        model=Shift
+        include_fk=True
+        fields = ("id", "battery_changes", "all_completed")
+
+    def get_all_completed(self, obj):
+        return all(change.completed == True for change in obj.battery_changes)