build(config): add docker support and project documentation

- Integrate Docker Spring Boot application plugin for containerization
- Bump project version to 0.1
- Include MIT license and project README
- Ignore IDE configuration files in version control

build.gradle.kts

@@ -3,10 +3,11 @@ plugins {
     kotlin("plugin.spring") version "2.2.21"
     id("org.springframework.boot") version "4.0.6"
     id("io.spring.dependency-management") version "1.1.7"
+    id("com.bmuschko.docker-spring-boot-application") version "10.0.0"
 }
 
 group = "com.msksbr"
-version = "0.0.1-SNAPSHOT"
+version = "0.1"
 description = "bookMgr"
 
 java {
@@ -58,3 +59,23 @@ tasks.bootJar {
     exclude("application-dev.yaml")
 }
 
+val giteaRegistry = System.getenv("GITEA_REGISTRY") ?: "gitea.example.com"
+val giteaUser     = System.getenv("GITEA_USERNAME") ?: ""
+val giteaToken    = System.getenv("GITEA_TOKEN") ?: ""
+
+docker {
+    springBootApplication {
+        baseImage.set("bellsoft/liberica-runtime-container:jre-21-slim-musl")
+        ports.set(listOf(8080))
+        images.set(setOf(
+            "$giteaRegistry/$giteaUser/bookMgr:${project.version}",
+            "$giteaRegistry/$giteaUser/bookMgr:latest"
+        ))
+        jvmArgs.set(listOf("-Xmx512m", "-Dfile.encoding=UTF-8"))
+    }
+    registryCredentials {
+        url.set("https://$giteaRegistry")
+        username.set(giteaUser)
+        password.set(giteaToken)
+    }
+}