diff --git a/src/main/java/nl/andrewlalis/teaching_assistant_assistant/TeachingAssistantAssistantApplication.java b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/TeachingAssistantAssistantApplication.java
index c5adf7d..5b31ab9 100644
--- a/src/main/java/nl/andrewlalis/teaching_assistant_assistant/TeachingAssistantAssistantApplication.java
+++ b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/TeachingAssistantAssistantApplication.java
@@ -1,9 +1,5 @@
 package nl.andrewlalis.teaching_assistant_assistant;
 
-import nl.andrewlalis.teaching_assistant_assistant.model.repositories.CourseRepository;
-import nl.andrewlalis.teaching_assistant_assistant.model.repositories.PersonRepository;
-import nl.andrewlalis.teaching_assistant_assistant.model.repositories.TeamRepository;
-import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.CommandLineRunner;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
@@ -11,15 +7,6 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 @SpringBootApplication
 public class TeachingAssistantAssistantApplication implements CommandLineRunner {
 
-	@Autowired
-	CourseRepository courseRepository;
-
-	@Autowired
-	TeamRepository teamRepository;
-
-	@Autowired
-	PersonRepository personRepository;
-
 	public static void main(String[] args) {
 		SpringApplication.run(TeachingAssistantAssistantApplication.class, args);
 	}
diff --git a/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/repositories/UserRepository.java b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/repositories/UserRepository.java
new file mode 100644
index 0000000..aa8e696
--- /dev/null
+++ b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/repositories/UserRepository.java
@@ -0,0 +1,10 @@
+package nl.andrewlalis.teaching_assistant_assistant.model.repositories;
+
+import nl.andrewlalis.teaching_assistant_assistant.model.security.User;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.util.Optional;
+
+public interface UserRepository extends JpaRepository<User, Long> {
+    Optional<User> findByUsername(String username);
+}
diff --git a/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/User.java b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/User.java
new file mode 100644
index 0000000..49083cd
--- /dev/null
+++ b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/User.java
@@ -0,0 +1,42 @@
+package nl.andrewlalis.teaching_assistant_assistant.model.security;
+
+import nl.andrewlalis.teaching_assistant_assistant.model.BasicEntity;
+import nl.andrewlalis.teaching_assistant_assistant.model.people.Person;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.JoinColumn;
+import javax.persistence.OneToOne;
+
+/**
+ * Represents a user of the website with some credentials.
+ */
+@Entity
+public class User extends BasicEntity {
+
+    /**
+     * A unique username for the user.
+     */
+    @Column(nullable = false, unique = true)
+    private String username;
+
+    @Column
+    private String password;
+
+    @OneToOne
+    @JoinColumn(name = "person_id", nullable = true, referencedColumnName = "id")
+    private Person person;
+
+    public String getUsername() {
+        return this.username;
+    }
+
+    public String getPassword() {
+        return this.password;
+    }
+
+    public Person getPerson() {
+        return this.person;
+    }
+
+}
diff --git a/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/UserDetails.java b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/UserDetails.java
new file mode 100644
index 0000000..f4730ee
--- /dev/null
+++ b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/UserDetails.java
@@ -0,0 +1,49 @@
+package nl.andrewlalis.teaching_assistant_assistant.model.security;
+
+import org.springframework.security.core.GrantedAuthority;
+
+import java.util.Collection;
+
+public class UserDetails implements org.springframework.security.core.userdetails.UserDetails {
+
+    private User user;
+
+    public UserDetails(User user) {
+        this.user = user;
+    }
+
+    @Override
+    public Collection<? extends GrantedAuthority> getAuthorities() {
+        return null;
+    }
+
+    @Override
+    public String getPassword() {
+        return this.user.getPassword();
+    }
+
+    @Override
+    public String getUsername() {
+        return this.user.getUsername();
+    }
+
+    @Override
+    public boolean isAccountNonExpired() {
+        return true;
+    }
+
+    @Override
+    public boolean isAccountNonLocked() {
+        return true;
+    }
+
+    @Override
+    public boolean isCredentialsNonExpired() {
+        return true;
+    }
+
+    @Override
+    public boolean isEnabled() {
+        return true;
+    }
+}
diff --git a/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/UserDetailsService.java b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/UserDetailsService.java
new file mode 100644
index 0000000..6658a33
--- /dev/null
+++ b/src/main/java/nl/andrewlalis/teaching_assistant_assistant/model/security/UserDetailsService.java
@@ -0,0 +1,24 @@
+package nl.andrewlalis.teaching_assistant_assistant.model.security;
+
+import nl.andrewlalis.teaching_assistant_assistant.model.repositories.UserRepository;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+
+import java.util.Optional;
+
+public class UserDetailsService implements org.springframework.security.core.userdetails.UserDetailsService {
+
+    private UserRepository userRepository;
+
+    protected UserDetailsService(UserRepository userRepository) {
+        this.userRepository = userRepository;
+    }
+
+    @Override
+    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
+        Optional<User> optionalUser = this.userRepository.findByUsername(username);
+        optionalUser.orElseThrow(() -> new UsernameNotFoundException("Username not found."));
+
+        return new nl.andrewlalis.teaching_assistant_assistant.model.security.UserDetails(optionalUser.get());
+    }
+}