init: readme 작성 하네스 설계

tests/fixtures/valid-backend/build.gradle.kts

@@ -0,0 +1,14 @@
+plugins {
+    java
+}
+
+group = "com.example.demo"
+version = "0.1.0"
+
+tasks.register("bootRun") {
+    description = "Run the application"
+}
+
+tasks.register("test") {
+    description = "Run the tests"
+}