Create the schema

[githubbob42]

Mingle Card: 1608 Create the schema required to make this time entry in an Enterprise Edition ORG

Even though we should not be working ahead of the card we should go ahead and create a pretty full schema now since SFDC makes incremental updates challenging. 

Turn on track history for every field

• Job lookup set to clear the value when the parent is deleted, value not required
• Ticket lookup set to clear the value when the parent is deleted, value not required  - TMP: let's hold off on this one for now since we don't have a use case yet for it.
• Ticket Item lookup set to clear the value when the parent is deleted, value not required
• Picklist called Chargecode.  The default choices are Training, Shop Time, Vacation, Sick Time.
• Checkbox for billable/non-billable
• Start Time, not required
• End Time not required
• Input Hours, decimal, not required
• Total Hours, calculated field that selects either (stop time - start time) or input hours, whichever has a value
• User, required. or the SFDC workflow will not work AND our customers will be able to use as many users without paying us. - RL note: the UI doesn't have the required checkbox for a lookup relationship to User, but we would have trigger to enforce that.
• Comments, Text Area (Long), not required
• Date for this time card entry - default to Today(). This will only be used with the Input Hours
• Status, picklist, not required. Values are Submitted, Approved, Rejected
• RLUO 2/4/2014 14:40 - Add Ticket_Item_ID - external ID, Unique, not required. Used in #1612 for TicketItem trigger to automatically create/update Timecard upon TicketItem upsert. Without this external ID, all TicketItem update would need to query Timecard to check to determine either insert or update timecard. Using external ID, SFDC would insert or update the timecard accordingly. 
• Timecard: add validation rule StartTime<=EndTime

[githubbob42]

Story: #1404 Field user enters time for a job (Mingle)