ModuleDagger.kt

@Module
class DataBaseModule {
    @Provides
    @Singleton
    fun provideRoom(app: Application): AppDatabase = Room
            .databaseBuilder(app, AppDatabase::class.java, BuildConfig.APPLICATION_ID)
            .build()

    @Provides
    @Singleton
    fun provideHotelsDao(room: AppDatabase): HotelsDao = room.hotelsDao()

    @Provides
    @Singleton
    fun provideVisitorsDao(room: AppDatabase): VisitorsDao = room.visitorsDao()
}