Add server connection check to the front app.

src/main/resources/application.properties

@@ -11,5 +11,6 @@ spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults = false
 # ***********************************************
 # Application custom parameters
 # ***********************************************
+minager.version=0.0.1
 minecraft.server.path=/home/minecraft/server
 minecraft.server.shell.name=minecraft-server.sh