Add ignore_conflicts to bulk_create_with_history

[shihanng]

Description

If we are to support ignore_conflicts, we need to consider that not all item in the list of objects will be bulk created due to conflicts. Then, we also need to make sure that we create history records only for those objects that we created successfully. Unfortunately, we can't rely on the return value of bulk_create API because it returns all objects including those it ignores. Therefore, whenever ignore_conflicts=True we need to "force" the second transaction to query the created objects.

Related Issue

Close #732

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have run the make format command to format my code
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have added my name and/or github handle to AUTHORS.rst
• I have added my change to CHANGES.rst
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #733 (6dc1536) into master (c05255c) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #733   +/-   ##
=======================================
  Coverage   97.44%   97.44%           
=======================================
  Files          18       18           
  Lines         980      980           
  Branches      148      148           
=======================================
  Hits          955      955           
  Misses         12       12           
  Partials       13       13           

Impacted Files	Coverage Δ
simple_history/utils.py	93.93% <100.00%> (ø)

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[shihanng]

Hi, I am opening this PR to propose a solution to #732. Please take a look and let me know what you think? Thank you.

[ThePumpingLemma]

@shihanng would you mind rebasing? Think it looks good otherwise but I'll let @rossmechanic chime in.

[shihanng]

@ThePumpingLemma, rebased. Thank you.

[ThePumpingLemma]

Thanks!

[ThePumpingLemma]

Not sure code climate is ever going to run. /shrug