Add correct and incorrect

[Robert3141]

Is your feature request related to a problem? Please describe.
When learning it's best to target your weak spot. Telling the app if the word is good is a good start.

Describe the solution you'd like
Have a green tick and red cross to say if you've learnt it. These are are saved and there's an option to work on incorrect problems.

Describe alternatives you've considered
Star words. This is the same idea.

Additional context
The main activity. The flashcards need resizing for this to occur

[Robert3141]

Might add in later flutter releases