Moded group updateing to a updateusergroup action model

ref #76

src/models/actions/update/UpdateUserGroup.ts

@@ -0,0 +1,39 @@
+import { IsInt, IsOptional, IsString } from 'class-validator';
+import { UserGroup } from '../../entities/UserGroup';
+
+/**
+ * This class is used to update a UserGroup entity (via put request).
+ */
+export class UpdateUserGroup {
+
+    /**
+     * The updated group's id.
+     * This shouldn't have changed but it is here in case anyone ever wants to enable id changes (whyever they would want to).
+     */
+    @IsInt()
+    id: number;
+
+    /**
+     * The updated group's name.
+     */
+    @IsString()
+    name: string;
+
+    /**
+     * The updated groups's description.
+     */
+    @IsString()
+    @IsOptional()
+    description?: string;
+
+    /**
+     * Updates a group entity based on this.
+     * @param group The group that shall be updated.
+     */
+    public async update(group: UserGroup): Promise<UserGroup> {
+        group.name = this.name;
+        group.description = this.description;
+
+        return group;
+    }
+}