#86 Update - Form validations

[mosdevly]

Add validations at the database and view levels to properly redirect users when an error occurs while signing up and logging in.

Friendly Reminder Checklist:

• [x] Code follows guidelines [follows guidelines](https://github.com/openoakland/TrashTalk/blob/master/CONTRIBUTE.md#codeguidelines
• [x] Tests have passed locally.
• [x] Linter score is 7.5 or above.
• [x] References to relevant issues added in the description.
• [x] Updates to migrations, tests and requirements are included as necessary.

@protosac

Description: EDIT ME.