Add all layers.

sportshub-domain/pom.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.sportshub</groupId>
+        <artifactId>sportshub-parent</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+
+    <artifactId>sportshub-domain</artifactId>
+
+    <name>sportshub-domain</name>
+    <description>Demo project for Spring Boot</description>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>16</source>
+                    <target>16</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <packaging>jar</packaging>
+</project>

sportshub-domain/src/main/java/org/sportshub/domain/user/model/User.java

@@ -0,0 +1,8 @@
+package org.sportshub.domain.user.model;
+
+import java.util.UUID;
+
+public record User(
+    UUID id,
+    String password
+) {}

sportshub-domain/src/main/java/org/sportshub/domain/user/port/UserPort.java

@@ -0,0 +1,10 @@
+package org.sportshub.domain.user.port;
+
+import java.util.Optional;
+import java.util.UUID;
+
+import org.sportshub.domain.user.model.User;
+
+public interface UserPort {
+    Optional<User> findById(UUID userId);
+}