常用GEM的基本使用无标题文章

bootstrap-sass

1. 添加gem并且bundle install

## 务必确保顺序关系
gem 'bootstrap-sass', '~> 3.3', '>= 3.3.6'
gem 'sass-rails', '>= 3.2'  

2. 导入bootstrap样式表(app/assets/stylesheets/application.scss)

@import "bootstrap-sprockets";
@import "bootstrap";

3. 修改app/assets/stylesheets/application.scss

去掉 `= require_self 、= require_tree`  使用`@import`

4. 引入JavaScript文件

//  app/assets/javascripts/application.js
//= require jquery
//= require bootstrap-sprockets

CarrierWave

用来上传文件的gem

安装

gem 'carrierwave'
$ bundle install

基本使用（以上传头像为例）

1. 生成uploader

rails generate uploader Avatar  ## 产生了app/uploaders/avatar_uploader.rb

2. 为user表添加avatar字段

rails g migration add_avatar_to_user avatar:string

3. 挂载uploader

class User < ActiveRecord::Base
   mount_uploader :avatar, AvatarUploader
 end