Added support for django-nonrel string AutoField primary key.
Added test to demonstrate the custom foreignkey bug
Added check for nonrel db type.
Converted `CustomForeignKeyField` into an importable non-dynamic class
Only run migration state test in 1.7 or greater
Patch `CustomForeignKeyField.do_related_class` method for migrations
Don't set related object for migrations
Factor auto field logic to its own method, detect engine using writable route
Merge pull request #125 from DAV3HIT3/non-rel-support
Merge pull request #126
Document changes and add David Hite to authors
Cleanup and linting
Release 1.5.1
Produce erroring migration test
explicitly override db_constraint in `CustomForeignKey.__init__()`
don't bother generating reverse relation for `CustomForeignKey`
Added 'makemigration' command to tests
Make db_constraint unflagging backward compatible
Cleanup, fix test declaration
Merge pull request #2 from treyhunner/fix-additional-migration

Fix additional migration