This was an error from using cancan and not using a column name.

ability.rb

class Ability
  include CanCan::Ability

  def initialize(user)
    #user ||= User.new # guest user not logged in.

    if user.is? :admin
      can :manage, :all
    elsif user.is? :sre
      can :manage, :all
    else
      can :read, :all
      # This is the model having problems below
      can :manage, Deployment, :production? => false
      can :manage, ComputeResource, :production? => false
      cannot :read, Userdata
    end
  end
end

deployment.rb

class Deployment < ActiveRecord::Base
  attr_accessible :jiralink

  has_many :audit_logs, :as => :auditable
  has_many :compute_resources

  def name
    "Deploy ##{self.id}"
  end

  def production?
    compute_resources.any?(&:production?)
  end
end

deployments_controller.rb

class DeploymentsController < ApplicationController
  before_filter :authenticate_user!
  load_and_authorize_resource :deployment

  def index
    @deployments = Deployment.order("created_at DESC").paginate(:page => params[:page], :per_page => 4)
    @package_types = PackageType.all
  end

  def show
    @deployment = Deployment.find(params[:id])
    @compute_resources = @deployment.compute_resources.paginate(:page => params[:compute_resource_page], :per_page => 4)
    @package_types_hash = @compute_resources.each.inject({}) do |r,e|
      key = e.package.package_type.name
      r[key] = (r.has_key?(key) ? r[key] : 0) + 1
      r
    end
    @audit_logs = @deployment.audit_logs.paginate(:page => params[:audit_logs_page], :per_page => 10).order("created_at DESC")
  end

  def new
    @deployment = Deployment.new()
    @package_types = PackageType.all
    if current_user.prod_admin?
      @datacenters = Datacenter.all
    else
      @datacenters = Datacenter.where("production = false")
    end
  end

  def create
    # Pull in Params
    @deployment = Deployment.new(params[:deployment])
    @package_config = params[:package_config]

    if @deployment.save
      flash.now[:success] = "Saved Deployment ##{@deployment.id}"
    end

# ...obf... #

    # Render Page
    flash.now[:notify] = "New Deployment params below"
    redirect_to @deployment
  end

end

NoMethodError

Started GET "/deployments/new" for 172.16.228.1 at 2013-01-03 09:17:13 -0700
Processing by DeploymentsController#new as HTML
  User Load (0.1ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 1 LIMIT 1
Completed 500 Internal Server Error in 5ms

NoMethodError (undefined method `production?=' for #<Deployment:0x000000055e45e8>):
  activemodel (3.2.8) lib/active_model/attribute_methods.rb:407:in `method_missing'
  activerecord (3.2.8) lib/active_record/attribute_methods.rb:149:in `method_missing'
  cancan (1.6.8) lib/cancan/controller_resource.rb:92:in `block in assign_attributes'
  cancan (1.6.8) lib/cancan/controller_resource.rb:91:in `each'
  cancan (1.6.8) lib/cancan/controller_resource.rb:91:in `assign_attributes'
  cancan (1.6.8) lib/cancan/controller_resource.rb:86:in `build_resource'
  cancan (1.6.8) lib/cancan/controller_resource.rb:66:in `load_resource_instance'
  cancan (1.6.8) lib/cancan/controller_resource.rb:32:in `load_resource'
  cancan (1.6.8) lib/cancan/controller_resource.rb:25:in `load_and_authorize_resource'
  cancan (1.6.8) lib/cancan/controller_resource.rb:10:in `block in add_before_filter'
  activesupport (3.2.8) lib/active_support/callbacks.rb:429:in `_run__4432566367038161022__process_action__642984099824367399__callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.8) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.8) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (3.2.8) lib/action_controller/metal/rescue.rb:29:in `process_action'
  actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
  activesupport (3.2.8) lib/active_support/notifications.rb:123:in `block in instrument'
  activesupport (3.2.8) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
  activesupport (3.2.8) lib/active_support/notifications.rb:123:in `instrument'
  actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
  actionpack (3.2.8) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
  activerecord (3.2.8) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
  actionpack (3.2.8) lib/abstract_controller/base.rb:121:in `process'
  actionpack (3.2.8) lib/abstract_controller/rendering.rb:45:in `process'
  actionpack (3.2.8) lib/action_controller/metal.rb:203:in `dispatch'
  actionpack (3.2.8) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
  actionpack (3.2.8) lib/action_controller/metal.rb:246:in `block in action'
  actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:73:in `call'
  actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
  actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:36:in `call'
  journey (1.0.4) lib/journey/router.rb:68:in `block in call'
  journey (1.0.4) lib/journey/router.rb:56:in `each'
  journey (1.0.4) lib/journey/router.rb:56:in `call'
  actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:600:in `call'
  warden (1.2.1) lib/warden/manager.rb:35:in `block in call'
  warden (1.2.1) lib/warden/manager.rb:34:in `catch'
  warden (1.2.1) lib/warden/manager.rb:34:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
  rack (1.4.1) lib/rack/etag.rb:23:in `call'
  rack (1.4.1) lib/rack/conditionalget.rb:25:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/head.rb:14:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/flash.rb:242:in `call'
  rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context'
  rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/cookies.rb:339:in `call'
  activerecord (3.2.8) lib/active_record/query_cache.rb:64:in `call'
  activerecord (3.2.8) lib/active_record/connection_adapters/abstract/connection_pool.rb:473:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
  activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `_run__319413531238084155__call__1038391992056911568__callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `__run_callback'
  activesupport (3.2.8) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
  activesupport (3.2.8) lib/active_support/callbacks.rb:81:in `run_callbacks'
  actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/reloader.rb:65:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
  railties (3.2.8) lib/rails/rack/logger.rb:26:in `call_app'
  railties (3.2.8) lib/rails/rack/logger.rb:16:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/request_id.rb:22:in `call'
  rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
  rack (1.4.1) lib/rack/runtime.rb:17:in `call'
  activesupport (3.2.8) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.4.1) lib/rack/lock.rb:15:in `call'
  actionpack (3.2.8) lib/action_dispatch/middleware/static.rb:62:in `call'
  railties (3.2.8) lib/rails/engine.rb:479:in `call'
  railties (3.2.8) lib/rails/application.rb:223:in `call'
  rack (1.4.1) lib/rack/content_length.rb:14:in `call'
  railties (3.2.8) lib/rails/rack/log_tailer.rb:17:in `call'
  rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
  /usr/local/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
  /usr/local/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
  /usr/local/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'


  Rendered /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.0ms)
  Rendered /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (0.7ms)
  Rendered /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (5.4ms)