feat: add createdAt field to Todo entity and update database migration script

backend/pom.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 	<parent>
@@ -69,8 +70,19 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-actuator</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-flyway</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.flywaydb</groupId>
+			<artifactId>flyway-core</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.flywaydb</groupId>
+			<artifactId>flyway-database-postgresql</artifactId>
+		</dependency>
 	</dependencies>
-
 	<build>
 		<plugins>
 			<plugin>

backend/src/main/java/com/todo/backend/model/Todo.java

@@ -1,5 +1,7 @@
 package com.todo.backend.model;
 
+import java.time.LocalDateTime;
+
 import jakarta.persistence.*;
 
 @Entity
@@ -19,6 +21,9 @@ public class Todo {
     @Column(nullable = false)
     private boolean completed = false;
 
+    @Column(nullable = false, updatable = false)
+    private LocalDateTime createdAt = LocalDateTime.now();
+
     // Default constructor is required by JPA
     public Todo() {
     }
@@ -62,4 +67,9 @@ public class Todo {
     public void setCompleted(boolean completed) {
         this.completed = completed;
     }
+
+    public LocalDateTime getCreatedAt() {
+        return createdAt;
+    }
+
 }

backend/src/main/resources/application.properties

@@ -1,10 +1,14 @@
-# backend/src/main/resources/application.properties
-
 server.port=8082
 server.servlet.context-path=/api
 spring.application.name=backend
 
-spring.jpa.hibernate.ddl-auto=update
+# Flyway
+spring.flyway.enabled=true
+spring.flyway.locations=classpath:db/migration
+spring.flyway.baseline-on-migrate=true
+
+# Database
+spring.jpa.hibernate.ddl-auto=none
 spring.jpa.show-sql=true
 spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
 management.endpoints.web.exposure.include=health,info,metrics

backend/src/main/resources/db/migration/V1__init.sql

@@ -0,0 +1,7 @@
+CREATE TABLE todos (
+    id BIGSERIAL PRIMARY KEY,
+    title VARCHAR(255) NOT NULL,
+    description TEXT,
+    completed BOOLEAN NOT NULL DEFAULT FALSE,
+    created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT NOW()
+);