#10 楼 @zj0713001 的确是这样！不过这个不影响吧？

      Your bundle is complete!
       Gems in the groups development and test were not installed.
       It was installed into ./vendor/bundle
       Bundle completed (18.44s)
       Cleaning up the bundler cache.
-----> Writing config/database.yml to read from DATABASE_URL
       Detected manifest file, assuming assets were compiled locally
-----> Discovering process types
       Procfile declares types -> (none)
       Default types for Ruby  -> console, rake, web, worker

-----> Compressing... done, 21.1MB
-----> Launching... done, v6
       http://rocky-fortress-5190.herokuapp.com deployed to Heroku

To [email protected]:rocky-fortress-5190.git
 * [new branch]      master -> master

今天在另一台电脑重新搭建了配置了下，竟然直接成功了，不需要改 database.yml

development:
  adapter: sqlite3
  database: db/development.sqlite3
  pool: 5
  timeout: 5000

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  adapter: sqlite3
  database: db/test.sqlite3
  pool: 5
  timeout: 5000

production:
  adapter: sqlite3
  database: db/production.sqlite3
  pool: 5
  timeout: 5000

#8 楼 @alsotang @zj0713001 我去试试，预感还是不行，就如@alsotang说的，安装 development 里面的东西了。

#2 楼 @chunlea 我是已经在 gemfile 里添加 pg 到 production 的

真不好意思！这几天忙，现在才回复你们。

#1 楼 @zj0713001 我在学习一本教材《Ruby on Rails Tutorial》里面，提到要这么做，下面是详细的 gemfile

source 'https://rubygems.org'
ruby '2.0.0'
#ruby-gemset=railstutorial_rails_4_0

gem 'rails', '4.0.2'

group :development do
  gem 'sqlite3', '1.3.8'
end

gem 'sass-rails', '4.0.1'
gem 'uglifier', '2.1.1'
gem 'coffee-rails', '4.0.1'
gem 'jquery-rails', '3.0.4'
gem 'turbolinks', '1.1.1'
gem 'jbuilder', '1.0.2'

group :doc do
  gem 'sdoc', '0.3.20', require: false
end

group :production do
  gem 'pg', '0.15.1'
  gem 'rails_12factor', '0.0.2'
end