兼容性问题？rake DB：Migrate-参数数错误（1对0）

Question

我试图运行一个简单的迁移，我得到了这个错误。我想是某种兼容性错误。如何修复它，如何避免将来出现兼容性问题？

Migration: `class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users do |t|
      t.string :nume
      t.string :email
      t.string :localitate

      t.timestamps 
    end
  end
end
___________________

source 'https://rubygems.org'


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.0.beta4'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0.0.beta1'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.1.0'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use jQuery as the JavaScript library
gem 'jquery-rails', '~> 4.0.0.beta2'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc

# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Unicorn as the app server
# gem 'unicorn'

# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug'

  # Access an IRB console on exception pages or by using <%= console %> in views
  gem 'web-console', '~> 2.0.0.beta4'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :jruby]

___________

Answer 1

答案就在这里：脚手架后不能迁移数据库。第2.2节Ruby on Rails教程Michael Hartl

您需要按照那里的指定安装arel gem。