Implement a better error message system #65
Description
There is currently no way for the user to understand when an error has occurred. For example, when filling out the Register form, the user should understand when one of their fields are missing. Another example is creating a Project but inputting incorrect fields.
HOW TO IMPLEMENT:
One idea of implementing is adding a Redux action to be triggered when a call to the back-end returns with an error code. Front-end components that are listening to this action (eg. useEffect()) could render an error message. We could also make use of the Alert component that already exists in the front-end.