User creation errors cause server exception

[alexander-bauer]

For example, creating a user which shares an email with an existing user will raise sqlalchemy.exc.IntegrityError, and creating a user with an empty password will raise builtins.ValueError.

[Mjacks3]

@alexander-bauer is this still an issue? I can't replicate it. If so I may need to switch over to a linux dev env.

[alexander-bauer]

@Mjacks3 I'll test in a moment, but if you need a Linux dev environment, you can use the demo site.

[Mjacks3]

duplicate of #49