added location dao and repository

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

@@ -1,15 +1,33 @@
 package com.a1.nextlocation.data;
 
+import androidx.annotation.NonNull;
+import androidx.room.Entity;
+import androidx.room.PrimaryKey;
+
+import org.jetbrains.annotations.NotNull;
+
+@Entity(tableName = "location")
 public class Location {
+
+    @PrimaryKey
+    @NonNull
     private String name;
+
     private String coordinates;
     private String description;
 
+    public Location(@NotNull String name, String coordinates, String description) {
+        this.name = name;
+        this.coordinates = coordinates;
+        this.description = description;
+    }
+
+    @NotNull
     public String getName() {
         return name;
     }
 
-    public void setName(String name) {
+    public void setName(@NotNull String name) {
         this.name = name;
     }