生成Micropost模型

与生成User模型类似，调用下面的脚手架指令生成Micropost模型:

[fangpeng@vps1 rails.pureage.info]$ rails generate scaffold Micropost content:string user_id:integer
      invoke  active_record
      create    db/migrate/20150405180434_create_microposts.rb
      create    app/models/micropost.rb
      invoke    test_unit
      create      test/models/micropost_test.rb
      create      test/fixtures/microposts.yml
      invoke  resource_route
       route    resources :microposts
      invoke  scaffold_controller
      create    app/controllers/microposts_controller.rb
      invoke    erb
      create      app/views/microposts
      create      app/views/microposts/index.html.erb
      create      app/views/microposts/edit.html.erb
      create      app/views/microposts/show.html.erb
      create      app/views/microposts/new.html.erb
      create      app/views/microposts/_form.html.erb
      invoke    test_unit
      create      test/controllers/microposts_controller_test.rb
      invoke    helper
      create      app/helpers/microposts_helper.rb
      invoke      test_unit
      invoke    jbuilder
      create      app/views/microposts/index.json.jbuilder
      create      app/views/microposts/show.json.jbuilder
      invoke  assets
      invoke    coffee
      create      app/assets/javascripts/microposts.coffee
      invoke    scss
      create      app/assets/stylesheets/microposts.scss
      invoke  scss
   identical    app/assets/stylesheets/scaffolds.scss

更新数据库

[fangpeng@vps1 rails.pureage.info]$ rake db:migrate
== 20150405180434 CreateMicroposts: migrating =================================
-- create_table(:microposts)
   -> 0.0114s
== 20150405180434 CreateMicroposts: migrated (0.0115s) ========================

操作Micropost接口

与User模型类似，可以使用各个rest的增删改查的接口来操作Micropost资源。

限制每条微博的长度不超过140个字

编辑app/models/micropost.rb

class Micropost < ActiveRecord::Base
  validates :content, length: { maximum: 140 }
end