mysql - Rails の日付プロパティが MySQL データベースに保存されない

Question

本番環境で MySQL を実行し、開発環境で SQLite を実行している Rails アプリケーションがあります。開発モードではすべて正常に動作しますが、本番環境では日時プロパティがデータベースに保存されません (created_at と updated_at も保存されません)。フィールドはnullではなく0000-00-00 00:00:00です。これはどのように可能ですか？色々調べましたが直りません。

スキーマ.rb:

# encoding: UTF-8
# This file is auto-generated from the current state of the database. Instead
# of editing this file, please use the migrations feature of Active Record to
# incrementally modify your database, and then regenerate this schema definition.
#
# Note that this schema.rb definition is the authoritative source for your
# database schema. If you need to create the application database on another
# system, you should be using db:schema:load, not running all the migrations
# from scratch. The latter is a flawed and unsustainable approach (the more migrations
# you'll amass, the slower it'll run and the greater likelihood for issues).
#
# It's strongly recommended to check this file into your version control system.

ActiveRecord::Schema.define(:version => 20130306100623) do

  create_table "announcements", :force => true do |t|
    t.string   "title"
    t.text     "text"
    t.integer  "user_id"
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
  end

  create_table "delayed_jobs", :force => true do |t|
    t.integer  "priority",   :default => 0
    t.integer  "attempts",   :default => 0
    t.text     "handler"
    t.text     "last_error"
    t.datetime "run_at"
    t.datetime "locked_at"
    t.datetime "failed_at"
    t.string   "locked_by"
    t.string   "queue"
    t.datetime "created_at",                :null => false
    t.datetime "updated_at",                :null => false
  end

  add_index "delayed_jobs", ["priority", "run_at"], :name => "delayed_jobs_priority"

  create_table "document_categories", :force => true do |t|
    t.string   "title"
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
  end

  create_table "documents", :force => true do |t|
    t.string   "file_file_name"
    t.string   "file_content_type"
    t.integer  "file_file_size"
    t.datetime "file_updated_at"
    t.datetime "created_at",        :null => false
    t.datetime "updated_at",        :null => false
    t.integer  "user_id"
    t.string   "title"
    t.text     "description"
    t.string   "ancestry"
    t.boolean  "folder"
  end

  add_index "documents", ["ancestry"], :name => "index_documents_on_ancestry"

  create_table "inventory_items", :force => true do |t|
    t.string   "object"
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
  end

  create_table "reservation_items", :force => true do |t|
    t.integer  "reservation_id"
    t.integer  "inventory_item_id"
    t.datetime "created_at",        :null => false
    t.datetime "updated_at",        :null => false
  end

  create_table "reservations", :force => true do |t|
    t.integer  "user_id"
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
    t.datetime "start_time"
    t.datetime "end_time"
  end

  create_table "users", :force => true do |t|
    t.string   "first_name"
    t.string   "insertion"
    t.string   "last_name"
    t.string   "telephone_prefix"
    t.string   "telephone_suffix"
    t.string   "address"
    t.string   "number"
    t.string   "postal_code"
    t.string   "city"
    t.date     "birthdate"
    t.string   "email",                  :default => "", :null => false
    t.string   "encrypted_password",     :default => "", :null => false
    t.string   "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.integer  "sign_in_count",          :default => 0
    t.datetime "current_sign_in_at"
    t.datetime "last_sign_in_at"
    t.string   "current_sign_in_ip"
    t.string   "last_sign_in_ip"
    t.datetime "created_at",                             :null => false
    t.datetime "updated_at",                             :null => false
    t.string   "telephone_mobile"
    t.integer  "admin"
    t.string   "avatar_file_name"
    t.string   "avatar_content_type"
    t.integer  "avatar_file_size"
    t.datetime "avatar_updated_at"
    t.string   "sex"
    t.string   "lovo_email"
  end

  add_index "users", ["email"], :name => "index_users_on_email", :unique => true
  add_index "users", ["reset_password_token"], :name => "index_users_on_reset_password_token", :unique => true

end

どうもありがとうございます！