Beside the function to save deck to database, all other features implemented. See description.

If deck name is invalid, error msg shows up and create button is disabled.
If the empty text field for entering card value is filled(valid or invalid), a new text field shows up.
If the value of a text field is deleted to empty(when there are two empty text fields), the first empty one is deleted.
Card will show the value of the text field with your cursor is inside. If the value is invalid, card becomes blank.
If the value in the text field is valid, a green check shows up.
Text field can be deleted by clicking on the X button.