better file concatenator

file_combine/build.gradle

@@ -1,10 +1,16 @@
 plugins {
 	id 'java'
+	id 'application'
+	id 'com.gradleup.shadow' version '8.3.5'
 }
 
 group = 'click.kamil.file_combine'
 version = '0.0.1-SNAPSHOT'
 
+application {
+	mainClass = 'click.kamil.file_combine.JavaConcatenator'
+}
+
 java {
 	toolchain {
 		languageVersion = JavaLanguageVersion.of(21)
@@ -22,6 +28,9 @@ repositories {
 }
 
 dependencies {
+	// Picocli
+	implementation 'info.picocli:picocli:4.7.6'
+
 	// deps for parsing java AST
 	implementation 'org.eclipse.jdt:org.eclipse.jdt.core:3.36.0'