Update build.gradle, .gitignore

.gitignore

@@ -1,3 +1,7 @@
 ./idea
 ./build
 .class
+gradlew
+/.gradle
+/.idea
+build/

build.gradle

@@ -1,6 +1,7 @@
 plugins {
     id 'org.jetbrains.kotlin.jvm' version '1.5.31'
     id 'java'
+    id 'application'
 }
 
 group 'org.praesecho'
@@ -25,6 +26,7 @@ repositories {
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib"
 
+
     // Flatlaf
     implementation 'com.formdev:flatlaf:1.6.1'
 
@@ -42,4 +44,14 @@ dependencies {
 
 test {
     useJUnitPlatform()
-}
+}
+
+jar {
+    duplicatesStrategy = 'exclude'
+    manifest {
+        attributes 'Main-Class': 'Rs2MapEditor'
+    }
+    from { configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) } }
+}
+
+mainClassName = "Rs2MapEditor"