fix FileSystemScanner.kt which would return Series with no books

added test user

komga/src/main/kotlin/org/gotson/komga/domain/service/FileSystemScanner.kt

@@ -24,7 +24,8 @@ class FileSystemScanner(
                     name = it.nameWithoutExtension,
                     url = it.toURI().toURL()
                 )
-              } ?: return@mapNotNull null
+              }
+          if (books.isNullOrEmpty()) return@mapNotNull null
           Serie(
               name = dir.name,
               url = dir.toURI().toURL(),

komga/src/main/kotlin/org/gotson/komga/infrastructure/security/SecurityConfiguration.kt

@@ -52,6 +52,7 @@ class SecurityConfiguration : WebSecurityConfigurerAdapter() {
   override fun configure(auth: AuthenticationManagerBuilder) {
     auth.inMemoryAuthentication()
         .withUser("admin").password("{noop}admin").roles("ADMIN", "USER")
+        .and().withUser("user").password("{noop}user").roles("USER")
   }
 
   @Bean