修复编辑时分类不正确的问题

src/views/discuss/add-edit.vue

@@ -344,6 +344,7 @@ export default {
 						
 							this.id = res.data.id
 							this.form.subject = res.data.subject
+							this.form.deriverName = res.data.category
 							// 发布按钮文案
 			        this.form.topicBtnText = res.data.topicbtntext == null ? '' : res.data.topicbtntext
 							this.form.commentBtnText = res.data.commentbtntext