Writing to Rails with a JSON API - ruby-on-rails

Question

I've been trying to write to a regular one model rails app from POSTman for a few days now, and can't figure out how to do it, or find any information on how to do it.
My app has a User model with a name field. All I'm trying to do is change the name remotely via JSON using POSTman.
Any help on how to do this is appreciated, including a link to a basic resource on how to do it.
I imagine this is pretty basic.
EDIT: here is a screenshot from the POSTman output
EDIT 2:
from server log:
Started PUT "/users/1.json" for 127.0.0.1 at 2013-07-17 16:53:36 -0400
Processing by UsersController#update as JSON
Parameters: {"name"=>"Jeff", "id"=>"1"}
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1 [["id", "1"]]
(0.1ms) begin transaction
(0.1ms) commit transaction
Completed 204 No Content in 3ms (ActiveRecord: 0.4ms)
The transaction is happening, but the record isn't actually being updated. Do I need to change something in the controller? It's just a regular rails generated controller with no changes.
EDIT 3:
Here is my output from just going to http://localhost:3000/users/1.json
{
"created_at": "2013-07-02T21:51:22Z",
"id": 1,
"name": "Arel",
"updated_at": "2013-07-02T21:51:22Z"
}
Again, I've changed nothing from the scaffold, and I haven't been able to figure out how to format the JSON to nest it under user like the answer suggests.
Here is the relevant part of my controller:
# GET /users/1
# GET /users/1.json
def show
#user = User.find(params[:id])
respond_to do |format|
format.html # show.html.erb
format.json { render json: #user }
end
end
# PUT /users/1
# PUT /users/1.json
def update
#user = User.find(params[:id])
respond_to do |format|
if #user.update_attributes(params[:user])
format.html { redirect_to #user, notice: 'User was successfully updated.' }
format.json { }
else
format.html { render action: "edit" }
format.json { render json: #user.errors, status: :unprocessable_entity }
end
end
end
I don't understand why this is so difficult. I'm just trying to update a name via JSON ...

Answer 1

For the controller you want to post to:
protect_from_forgery with: :null_session
or like from: How do I bypass protect_from_forgery in Rails 3 for a Facebook canvas app?
skip_before_filter :verify_authenticity_token, :only => [THE ACTION]
EDIT
Your JSON is incorrect... you are posting
{"name"=>"Jeff", "id"=>"1"}
Since your controller does user.update_attribute(params[:user]), your JSON needs to be under a user attribute
{
"id": 1,
"user": {
"name": "Jeff"
}
}
This will create a hash of
{"user"=>{"name"=>"Jeff"}, "id"=>"1"}