Fix user creation bug

src/main/java/com/eistgeist/flightsystem/model/User.java

@@ -25,6 +25,9 @@ public class User {
     @JsonProperty(access = JsonProperty.Access.READ_ONLY)
     private JourneyList journeys; /* The flights that user saved */
 
+    public User() {
+    }
+
     public User(String userName, String password) {
         this.userName = userName;
         this.password = password;

src/main/java/com/eistgeist/flightsystem/rest/UserController.java

@@ -6,6 +6,7 @@
 import io.swagger.v3.oas.annotations.Operation;
 import lombok.AllArgsConstructor;
 import org.apache.coyote.Response;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
@@ -22,7 +23,7 @@ public class UserController {
     @Operation(description = "Add a user and its password")
     public ResponseEntity<User> addUser(@RequestBody User user) {
         if(user == null) return (ResponseEntity<User>) ResponseEntity.badRequest();
-        return ResponseEntity.ok(userService.addUser(user));
+        return new ResponseEntity<User>(userService.addUser(user), HttpStatus.CREATED);
     }
 
     @GetMapping("")