Using Mongoose, how do I insert key value pairs as objects into an array via a form?

Consider the following simple schema:

var PostSchema = new Post({
  body : String,
  tags : []
}

Via a form POST (REST HTTP API that I'm developing), I would like to insert key/value pairs into the tags array so that the resulting mongodb document would look like:

{
  "body" : "This is the post body",
  "tags" : [
              {"Color" : "Orange"},
              {"Color" : "Blue"},
              {"Person" : "Ted"},
              {"Person" : "Fred"},
              {"Person" : "Joe"},
              {"Stone" : "Diamond"}
           ]
}

My question is, how do I name the form fields for tags to accomplish this? I was thinking something like tags[0][color] for each color, but that doesn't work, that creates a separate array for each key inside the tags array with a list of the values.