camel.rb

class Camel < ActiveRecord::Base
  def initialize(attributes = nil, options = {})
    super(underscore_keys(attributes), options)
  end

  def attributes=(new_attributes, guard_protected_attributes=nil)
    super(underscore_keys(new_attributes, guard_protected_attributes))
  end

  def serializable_hash(options = nil)
    Hash[super(options).map { |k,v| [k.to_s.camelize.uncapitalize,v] }]
  end

  private

  def underscore_keys(hash)
    Hash[hash.map { |k,v| [k.to_s.underscore.to_sym,v] }]
  end
end

camel_controller.rb

class CamelController < ApplicationController
  respond_to :json

  def index
    respond_with Camel.all
  end

  def create
    @camel = Camel.new(params[:camel])

    if @camel.save
      respond_with @camel, status: :created, location: @camel
    else
      respond_with @camel.errors, status: :unprocessable_entity
    end
  end

end