rails 4 nested attributes won't create has_many model - ruby-on-rails-4

Question

I'm new to rails and have spent way too many hours on this. Thanks a lot, in advance, for any help!
I can't seem to get fields_for and/or accepts_nested_attributes_for to work for my nested attributes.
I have a smash_client that has_many contracts and a form that tries to create a smash_client with a parameter and at the same time it tries to also set a parameter on the contract object. The contract belongs_to the smash_client.
I've tried a lot of different solutions and have read the docs but I'm still missing something. I get this in my params hash, in the smash_clients_controller.rb
..., "smash_client"=>{"name"=>"fasdf", "user"=>"adam"}, "smash_client_id"=>{"instance_type"=>"spot"},...
from
= form_for #smash_client do |f|
.field
= f.label :name
= f.text_field :name
.field
= fields_for :smash_client_id do |c|
%p
= c.radio_button :instance_type, 'spot'
= c.label :instance_type, 'spot'
= c.radio_button :instance_type, 'on_demand'
= c.label :instance_type, 'on demand'
.actions
= f.submit 'Save'
and
class SmashClient < ActiveRecord::Base
has_many :contracts, dependent: :destroy
accepts_nested_attributes_for :contracts, allow_destroy: true,
reject_if: proc { |attributes| attributes[:instance_type].blank? }
...
def new
#smash_client = SmashClient.new
3.times { #smash_client.contracts.build }
end
...
def smash_client_params
#smash_client_params = params.require(:smash_client).
permit( :user, :name, contracts_attributes: [:instance_type] )
end
end
and
class Contract < ActiveRecord::Base
belongs_to :smash_client
after_create :determine_instance_type_and_start
before_destroy :stop_instances
...
end
I think the nested params would work if I hard coded it because if I try something like this, in the console, I don't get errors and I get a new SmashClient and Contract.
smash_client_params = {name: 'something', user: 'blah', contracts_attributes: [{instance_type: 'spot'}]}
SmashClient.create( smash_client_params )
I tried using :contracts, #smash_client.contracts and a few other things in the fields_for section. Also tried using select and collection_select but I can't seem to nail down the form.
sorry for the long post. Hopefully I got all the useful info with nothing extra in the question.
I'd really appreciate some direction or answers.
Thanks in advance.

Answer 1

I finally found it. The :instance_type had to be whitelisted in the Contract model. Thanks again, kalyani. I appreciate the help. Here's the changes to the code above:
.field
= fields_for :contracts do |c|
= c.label :instance_type, 'spot instance'
= c.radio_button :instance_type, 'spot', checked: true
= c.label :instance_type, 'on demand instance'
= c.radio_button :instance_type, 'on_demand'
and
def contract_params
params.require(:contract).
permit(:id, :name, :instance_id, :smash_client_id, :instance_type)
end

Answer 2

Instead of : fields_for :smash_client_id do |c|
write it as: fields_for :contracts do |c|
Refer:
1. http://apidock.com/rails/ActionView/Helpers/FormHelper/fields_for
http://railscasts.com/episodes/196-nested-model-form-part-1
Rails 4 Nested Attributes Unpermitted Parameters ---- refer this for writing the code in controller and view the correct way