Add new category/tag from the admin sidebar

import { CollectionConfig } from 'payload/types';
import slug from '../fields/slug';

export type CategoryType = {
  title: string;
  slug: string;
};

const Category: CollectionConfig = {
  slug: 'categories',
  admin: {
    useAsTitle: 'title',
  },
  access: {
    read: () => true,
  },
  fields: [
    {
      name: 'title',
      label: 'Title',
      type: 'text',
      required: true,
    },
    slug(),
  ],
};

export { Category };

import { Field } from 'payload/types';

export const categories: Field = {
  name: 'categories',
  label: 'Categories',
  type: 'relationship',
  relationTo: 'categories',
  hasMany: true,
  admin: {
    position: 'sidebar',
  },
};

import { CollectionConfig } from 'payload/types';
import { categories } from '../fields/categories';
import { ImageSizeNames, ImageSizes, MediaSlugs } from '../tokens';

const MediaPhotos: CollectionConfig = {
  slug: MediaSlugs.mediaPhotos,
  access: {
    read: (): boolean => true, // Everyone can read Media
  },
  admin: {
    useAsTitle: 'filename',
  },
  upload: {
    adminThumbnail: ImageSizeNames.thumbnail,
    imageSizes: [...ImageSizes.PhotoImageSizes],
    staticURL: '/media/photos',
    staticDir: 'media/photos',
  },
  fields: [
    {
      name: 'alt',
      label: 'Alt Text',
      type: 'text',
      required: true,
    },
    categories, // <--- Here
  ],
};

export { MediaPhotos };