I am creating an blogging application in Node.js + MongoDB Database. I have used relational Database like MySQL before but this is my first experience with NoSQL database. So I would like to conform my MongoDB data models before I move further. 
I have decided my blogDB to have 3 collections
post_collection - stores information about that article
comment_collection - store information about comments on articles
user_info_collection - contains user inforamtion
  PostDB
{
  _"id" : ObjectID(...),
  "author": "author_name",
  "Date": new Date(....),
  "tag" : ["politics" , "war"],
  "post_title": "My first Article",
  "post_content": "Big big article"
  "likes": 23
  "access": "public"
}
  CommentDB
{
   "_id" : Objectid(...),
   "POST": "My First Article",
   "comment_by": "User_name",
   "comment": "MY comments"
}
  UserInfoDB
{
   "_id": ObjectID(...),
   "user": "User_name",
   "password": "My_password"
}
I would appreciate your comments.