Add integration tests for nested comments and reactions

src/test/resources/application.properties

@@ -0,0 +1,10 @@
+spring.datasource.url=jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1
+spring.datasource.driverClassName=org.h2.Driver
+spring.datasource.username=sa
+spring.datasource.password=
+spring.jpa.hibernate.ddl-auto=create-drop
+
+resend.api.key=dummy
+
+app.jwt.secret=TestSecret
+app.jwt.expiration=3600000