Adds JWT-based auth with refresh tokens

src/main/resources/application.properties

@@ -7,4 +7,7 @@ spring.jpa.properties.hibernate.type.preferred_uuid_jdbc_type=CHAR
 spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
 spring.datasource.url=${DB_URL}
 spring.datasource.username=${DB_USER}
-spring.datasource.password=${DB_PASSWORD}
+spring.datasource.password=${DB_PASSWORD}
+
+jwt.secret=${JWT_SECRET}
+jwt.expiration=30000