add WordRoomDatabase containing db class

app/src/main/java/world/whatever/task_roomdb/WordRoomDatabase.kt

@@ -0,0 +1,35 @@
+package world.whatever.task_roomdb
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+
+// Annotates class to be a Room Database with a table (entity) of the Word class
+@Database(entities = arrayOf(Word::class), version = 1, exportSchema = false)
+public abstract class WordRoomDatabase : RoomDatabase() {
+
+	abstract fun wordDao(): WordDao
+
+	companion object {
+		// Singleton prevents multiple instances of database opening at the
+		// same time.
+		@Volatile
+		private var INSTANCE: WordRoomDatabase? = null
+
+		fun getDatabase(context: Context): WordRoomDatabase {
+			// if the INSTANCE is not null, then return it,
+			// if it is, then create the database
+			return INSTANCE ?: synchronized(this) {
+				val instance = Room.databaseBuilder(
+					context.applicationContext,
+					WordRoomDatabase::class.java,
+					"word_database"
+				).build()
+				INSTANCE = instance
+				// return instance
+				instance
+			}
+		}
+	}
+}