added database and coupon and route daos

app/src/main/java/com/a1/nextlocation/data/Coupon.java

@@ -1,29 +1,48 @@
 package com.a1.nextlocation.data;
 
+import androidx.annotation.NonNull;
+import androidx.room.ColumnInfo;
+import androidx.room.Entity;
+import androidx.room.PrimaryKey;
+
+import org.jetbrains.annotations.NotNull;
+
+@Entity(tableName = "coupon")
 public class Coupon {
 
+    /**
+     * fields need to be public for the database to be able to use them
+     */
+    @PrimaryKey
+    @NonNull
+    @ColumnInfo(name = "code")
     private String code;
+
+    @ColumnInfo(name = "reward")
+    @NonNull
     private String reward;
 
 
-    public Coupon(String code, String reward) {
+    public Coupon(@NonNull String code, @NotNull String reward) {
         this.code = code;
         this.reward = reward;
     }
 
+    @NonNull
     public String getCode() {
         return code;
     }
 
-    public void setCode(String code) {
-        this.code = code;
-    }
-
+    @NonNull
     public String getReward() {
         return reward;
     }
 
-    public void setReward(String reward) {
+    public void setCode(@NonNull String code) {
+        this.code = code;
+    }
+
+    public void setReward(@NonNull String reward) {
         this.reward = reward;
     }
 }