Harden auth and improve user management

backend/pom.xml

@@ -37,6 +37,10 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-mail</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-security</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.springframework.security</groupId>
             <artifactId>spring-security-crypto</artifactId>