Migration for LMSUser and LMSCourse tables

[marcospri]

For:

• New LMSUser and LMSCourse tables #6575

Auto Generated from:

• Models for LMSCourse and LMSUser #6573

Testing

tox -e dev --run-command 'alembic upgrade head'     
dev run-test-pre: PYTHONHASHSEED='2671712126'
dev run-test-pre: commands[0] | pip-sync-faster requirements/dev.txt --pip-args --disable-pip-version-check
dev run-test: commands[0] | alembic upgrade head
INFO  [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO  [alembic.runtime.migration] Will assume transactional DDL.
INFO  [alembic.runtime.migration] Running upgrade 3d0c022c716c -> f13a876b8877, Create the lms_course and lms_user tables.