Updates to create job to handle scheduling

- If the job JSON contains a scheduling date then the new 'job_status" column is set to "scheduled"
- the date is persisted on the JOB row in the database
- Also the job WILL NOT be placed onto the queue of jobs. This is deferred to a later celery beat task.

app/schemas.py

@@ -1,10 +1,9 @@
 import re
 from datetime import (
     datetime,
-    date
-)
+    date,
+    timedelta)
 from flask_marshmallow.fields import fields
-
 from marshmallow import (
     post_load,
     ValidationError,
@@ -40,11 +39,21 @@ def _validate_positive_number(value, msg="Not a positive integer"):
         raise ValidationError(msg)
 
 
+def _validate_not_more_than_24_hours_in_future(dte, msg="Date cannot be more than 24hrs in the future"):
+    if dte > datetime.utcnow() + timedelta(hours=24):
+        raise ValidationError(msg)
+
+
 def _validate_not_in_future(dte, msg="Date cannot be in the future"):
     if dte > date.today():
         raise ValidationError(msg)
 
 
+def _validate_not_in_past(dte, msg="Date cannot be in the past"):
+    if dte < datetime.today():
+        raise ValidationError(msg)
+
+
 # TODO I think marshmallow provides a better integration and error handling.
 # Would be better to replace functionality in dao with the marshmallow supported
 # functionality.
@@ -210,6 +219,13 @@ class JobSchema(BaseSchema):
 
     job_status = field_for(models.JobStatus, 'name', required=False)
 
+    scheduled_for = fields.DateTime()
+
+    @validates('scheduled_for')
+    def validate_scheduled_for(self, value):
+        _validate_not_in_past(value)
+        _validate_not_more_than_24_hours_in_future(value)
+
     class Meta:
         model = models.Job
         exclude = ('notifications',)