Fix create_user issue

[jaapbrasser]

Description

Updated logic and API endpoint for 5.3 compat

Related Issue

Resolves #273

How Has This Been Tested?

• Ran existing tests

Screenshots (if appropriate):

Types of changes

What types of changes does your code introduce? Put an x in all the boxes that apply:

• 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:

Go over all the following points, and put an x in all the boxes that apply. If you're unsure about any of these, don't hesitate to ask. We're here to help!

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTION document.
• I have updated the CHANGELOG file accordingly for the version that this merge modifies.
• I have added tests to cover my changes.
• All new and existing tests passed.