Function booklibrs::actions::genres::add_genre

pub fn add_genre(
    genres: &mut Genres, 
    reader_base: &ReaderBase, 
    book_system: &BookSystem, 
    caretaker: &mut Caretaker, 
    app: &App, 
    lang: Lang
)

Function that adds new genre. If you have mistakes in input, program will let you know