many improvements

web/models.py

@@ -0,0 +1,31 @@
+from sqlalchemy import Column, DateTime, ForeignKey, Integer, String, Float, Boolean
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+
+Base = declarative_base()
+
+class SingleShift(Base):
+    __tablename__ = 'single_shift'
+    id  = Column(Integer, primary_key=True, index=True)
+    name = Column(String)
+    length = Column(Float)
+    balance_offset = Column(Float, nullable=True)
+    balance_weighting = Column(Float)
+    workers_required = Column(Float)
+    assign_as_block = Column(Boolean)
+    force_as_block = Column(Boolean)
+    hard_constrain_shift = Column(Boolean)
+    bank_holidays_only = Column(Boolean)
+    constraint_id = Column(Integer, ForeignKey('shift_constraint.id'))
+
+    constraint = relationship('ShiftConstraint')
+
+
+class ShiftConstraint(Base):
+    __tablename__ = 'shift_constraint'
+    id = Column(Integer, primary_key=True)
+    name = Column(String)
+    options = Column(Integer, nullable=True)
+
+