Rails 4迁移：Mysql2 ::错误：列'xxxx'的数据太长

Here is my schema.rb

这是我的schema.rb

  create_table "users", force: true do |t|
    t.string   "name",       limit: 6
    t.string   "email"
    t.datetime "created_at"
    t.datetime "updated_at"
  end
  create