activerecord - rails how to save a model with has_many through association -

i having models

// contains details of parties (users) class party < activerecord::base  has_many :party_races  has_many :races, :through=>:party_races end  // contains party_id , race_id  mappings class partyrace < activerecord::base  belongs_to :party  belongs_to :race end  // contains list of races asian,american,etc.. class race < activerecord::base  has_many :party_races  has_many :parties, :through => :party_races end 

now, lets i'm creating instance of party party_instance = party.new

how supposed add multiple races party_instance , save database ?

you use nested attributes make 1 form allows children. there many examples on site. read on following first:

• accepts nested attributes
• fields for
• a railscast use case