启动从ubuntu上的ruby gem下载的postgres服务器

当我运行rake:db从我的rails应用程序迁移时,我得到了这个输出:

rake aborted!
PG::ConnectionBad: could not connect to server: Connection refused
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5432?

/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:888:in `initialize'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:888:in `new'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:888:in `connect'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:568:in `initialize'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `new'
 /home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `postgresql_connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:435:in `new_connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:445:in `checkout_new_connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:416:in `acquire_connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:351:in `block in checkout'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:350:in `checkout'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block in connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:264:in `connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:541:in `retrieve_connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_handling.rb:113:in `retrieve_connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/connection_handling.rb:87:in `connection'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/migration.rb:910:in `initialize'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/migration.rb:807:in `new'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/migration.rb:807:in `up'
 /home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/migration.rb:785:in `migrate'
/home/ubuntu/.rvm/gems/ruby-2.1.2/gems/activerecord-4.1.4/lib/active_record/railties/databases.rake:34:in `block (2 levels) in '
/home/ubuntu/.rvm/gems/ruby-2.1.2/bin/ruby_executable_hooks:15:in `eval'
/home/ubuntu/.rvm/gems/ruby-2.1.2/bin/ruby_executable_hooks:15:in `
'

在我的gemfile中我有

gem 'pg'

在我的database.yml我有

default: &default
  adapter: postgresql
  encoding: unicode
  pool: 5

development:
  <<: *default
  database: fake_lunch_hub_development

test:
  <<: *default
  database: fake_lunch_hub_test


production:
  <<: *default
  database: fake_lunch_hub_production
  username: fake_lunch_hub
  password: <%= ENV['FAKE_LUNCH_HUB_DATABASE_PASSWORD'] %>

这个设置用于完美地连接到数据库,但我做了很多重构和重命名(项目不再被称为fake_lunch_hub),我将项目从我的本地机器(mac)移到亚马逊EC2实例(ubuntu)上.

Stackoverflow上有许多其他问题,它们使用psql提供解决方案,但是当我运行命令时

psql

我明白了:

The program 'psql' can be found in the following packages:
* postgresql-client-common
* postgres-xc-client
Try: sudo apt-get install 

我宁愿不下载一个新的postgres包,因为我已经从gem成功下载了它.

如何启动该服务器并接受连接？

编辑:

完整解决方案:

sudo apt-get install postgres
sudo su
su postgres
createuser ubuntu
createuser fake_lunch_hub
createdb fake_lunch_hub
exit
exit
rails server

解决问题