Added build with tomcat docker image

Dockerfile

@@ -0,0 +1,7 @@
+FROM gradle:jdk17-jammy as build
+WORKDIR /home/gradle/ModeratorElection
+COPY . /home/gradle/ModeratorElection
+RUN ./gradlew -Dvaadin.productionMode=true -Dvaadin.force.production.build=true -Pproduction clean war
+
+FROM tomcat:11.0
+COPY --from=build home/gradle/ModeratorElection/build/libs/ModeratorElection-plain.war /usr/local/tomcat/webapps/ROOT.war

build.gradle

@@ -10,6 +10,7 @@ plugins {
 	id 'io.spring.dependency-management' version '1.0.15.RELEASE'
 	id 'java'
 	id 'com.vaadin'
+	id 'war'
 }
 
 repositories {
@@ -32,6 +33,7 @@ dependencies {
 	testImplementation('org.springframework.boot:spring-boot-starter-test') {
 		exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
 	}
+	providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'
 }
 
 dependencyManagement {
@@ -40,6 +42,10 @@ dependencyManagement {
 	}
 }
 
+war {
+    enabled=true
+}
+
 test{
 	useJUnitPlatform()
 }

build.sh

@@ -0,0 +1,2 @@
+#!/bin/bash
+docker image build . -t moderator

src/main/java/com/ModeratorElection/MEApplication.java

@@ -2,9 +2,17 @@ package com.ModeratorElection;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
+import org.springframework.boot.builder.SpringApplicationBuilder;
 
 @SpringBootApplication
-public class MEApplication {
+public class MEApplication extends SpringBootServletInitializer {
+
+	@Override
+	protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
+		return application.sources(MEApplication.class);
+	}
+
 	public static void main(String[] args) {
 		SpringApplication.run(MEApplication.class, args);
 	}

src/main/resources/application.properties

@@ -6,6 +6,6 @@ spring.mustache.check-template-location = false
 vaadin.launch-browser=true
 # To improve the performance during development.
 # For more information https://vaadin.com/docs/latest/integrations/spring/configuration#special-configuration-parameters
-vaadin.allowed-packages = com.vaadin,org.vaadin,dev.hilla,com.example.application
+vaadin.allowed-packages = com.vaadin,org.vaadin,dev.hilla,com.ModeratorElection.ModeratorElection.ModeratorElectionApplication
 spring.jpa.defer-datasource-initialization = true
 membernames=${MEMBERNAMES:Micha,Ansgar,Clemens,Mattis,Erik,Mirco}