{
  post: {
    postId: 'postId',
    data: {
      images: [{
        postId: 'childPost',
        fileId: 'imageId',
      }]
    },
    parentId: 'parentId',
  },

  reactions: [{

  }],

  users: [{

  }],

  comments: [{

  }],
}

// -----------------------------------

GET /post/postId
-> the post
-> all reactions belong to post
-> all users belong to post
-> all comments belong to post
-> all children of post

UPDATE /post/postId
-> the post
-> parent post or all children of post

DELETE /post/postId
-> all mutated posts


childrenPosts = parentPost.children.map(id => postRepo.findById(id))

{
  post: [
  {
    postId: 'parentId',
    data: {
      text: '',
    },
    children: ['child1'],
  },
  {
    postId: 'child1',
    data: {
      imageFileId: 'img'
    }
    parentId: 'parentId',
  }]

  reactions: [{

  }],

  users: [{

  }],

  comments: [{

  }],
}

GET /v3/xxx-feed

{
  feedOrder: [id1, id2]
  posts: [

  ]
}

// ----------------------------------------------------------------------------------------
{
  post: {
    postId: 'parentId',
    data: {
      images: [{
        postId: 'postId',
        fileId: 'imageId',
      }]
    }
  },

  reactions: [{

  }],

  users: [{

  }],

  comments: [{

  }],
}