feat(series): Add slug field in SeriesForEditDTO

Author: gymynnym

src/main/kotlin/me/loghub/api/dto/series/SeriesForEditDTO.kt

@@ -4,6 +4,7 @@ import me.loghub.api.dto.series.chapter.SeriesChapterDTO
 
 data class SeriesForEditDTO(
     val id: Long,
+    val slug: String,
     val title: String,
     val description: String,
     val thumbnail: String,

src/main/kotlin/me/loghub/api/mapper/series/SeriesMapper.kt

@@ -38,6 +38,7 @@ object SeriesMapper {
 
     fun mapForEdit(series: Series) = SeriesForEditDTO(
         id = series.id!!,
+        slug = series.slug,
         title = series.title,
         description = series.description,
         thumbnail = series.thumbnail,