Added arch unit tests

pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>4.1.0-SNAPSHOT</version>
+        <version>4.1.0-M4</version>
         <relativePath/> <!-- lookup parent from repository -->
     </parent>
     <groupId>eu.andreasdahm.tbp</groupId>
@@ -15,6 +15,8 @@
     <properties>
         <java.version>25</java.version>
         <jwt.version>0.13.0</jwt.version>
+        <testcontainers.version>1.21.4</testcontainers.version>
+        <archunit.version>1.4.1</archunit.version>
     </properties>
     <dependencies>
         <!-- Spring -->
@@ -128,6 +130,29 @@
             <artifactId>spring-boot-devtools</artifactId>
             <scope>runtime</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-testcontainers</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>postgresql</artifactId>
+            <scope>test</scope>
+            <version>${testcontainers.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.tngtech.archunit</groupId>
+            <artifactId>archunit-junit5</artifactId>
+            <version>${archunit.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>