Problems with rails server - ruby-on-rails

Question

I am just getting started with ruby on rails and heroku. I am following the getting started guid on herokus website but have ran into a problem. I have logged into heroku, created an app as such rails new myapp --database=postgresql and then created a controller rails generate controller welcome index in the app/views/welcome/index.html.erb I just created a header saying hello world. When I start a local server and go to it, I get could not connect to server: No such file or directory Is the server running locally and accepting connections on Unix domain socket "/tmp/.s.PGSQL.5432"? and the output listed bellow in the terminal I followed another tutorial just for setting up rails without heroku and created the app like this rails new blog and then did the same as created a controller like in the heroku tutorial and everything worked fine, so I assume the problem is with rails new myapp --database=postgresql How would I fix this?
PG::ConnectionBad (could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
):
activerecord (4.0.2) lib/active_record/connection_adapters/postgresql_adapter.rb:831:in `initialize'
activerecord (4.0.2) lib/active_record/connection_adapters/postgresql_adapter.rb:831:in `new'
activerecord (4.0.2) lib/active_record/connection_adapters/postgresql_adapter.rb:831:in `connect'
activerecord (4.0.2) lib/active_record/connection_adapters/postgresql_adapter.rb:548:in `initialize'
activerecord (4.0.2) lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `new'
activerecord (4.0.2) lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `postgresql_connection'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:440:in `new_connection'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:450:in `checkout_new_connection'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:421:in `acquire_connection'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:356:in `block in checkout'
/Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/2.1.0/monitor.rb:211:in `mon_synchronize'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:355:in `checkout'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block in connection'
/Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/2.1.0/monitor.rb:211:in `mon_synchronize'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:264:in `connection'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:546:in `retrieve_connection'
activerecord (4.0.2) lib/active_record/connection_handling.rb:79:in `retrieve_connection'
activerecord (4.0.2) lib/active_record/connection_handling.rb:53:in `connection'
activerecord (4.0.2) lib/active_record/query_cache.rb:51:in `restore_query_cache_settings'
activerecord (4.0.2) lib/active_record/query_cache.rb:43:in `rescue in call'
activerecord (4.0.2) lib/active_record/query_cache.rb:32:in `call'
activerecord (4.0.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in `call'
activerecord (4.0.2) lib/active_record/migration.rb:369:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.0.2) lib/active_support/callbacks.rb:373:in `_run__4242016335734095215__call__callbacks'
activesupport (4.0.2) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.2) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/reloader.rb:64:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.2) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.2) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.0.2) lib/active_support/tagged_logging.rb:67:in `block in tagged'
activesupport (4.0.2) lib/active_support/tagged_logging.rb:25:in `tagged'
activesupport (4.0.2) lib/active_support/tagged_logging.rb:67:in `tagged'
railties (4.0.2) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.2) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.2) lib/action_dispatch/middleware/static.rb:64:in `call'
rack (1.5.2) lib/rack/sendfile.rb:112:in `call'
railties (4.0.2) lib/rails/engine.rb:511:in `call'
railties (4.0.2) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
/Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/2.1.0/webrick/httpserver.rb:138:in `service'
/Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/2.1.0/webrick/httpserver.rb:94:in `run'
/Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'
Rendered /Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/actionpack-4.0.2/lib/action_dispatch/middleware/templates/rescues/_source.erb (0.5ms)
Rendered /Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/actionpack-4.0.2/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.0ms)
Rendered /Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/actionpack-4.0.2/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (1.0ms)
Rendered /Users/mattmoss/.rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/actionpack-4.0.2/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (18.2ms)
Here is my database.yml
# PostgreSQL. Versions 8.2 and up are supported.
#
# Install the pg driver:
# gem install pg
# On OS X with Homebrew:
# gem install pg -- --with-pg-config=/usr/local/bin/pg_config
# On OS X with MacPorts:
# gem install pg -- --with-pg-config=/opt/local/lib/postgresql84/bin/pg_config
# On Windows:
# gem install pg
# Choose the win32 build.
# Install PostgreSQL and put its /bin directory on your path.
#
# Configure Using Gemfile
# gem 'pg'
#
development:
adapter: postgresql
encoding: unicode
database: myapp_development
pool: 5
password:
# Connect on a TCP socket. Omitted by default since the client uses a
# domain socket that doesn't need configuration. Windows does not have
# domain sockets, so uncomment these lines.
#host: localhost
# The TCP port the server listens on. Defaults to 5432.
# If your server runs on a different port number, change accordingly.
#port: 5432
# Schema search path. The server defaults to $user,public
#schema_search_path: myapp,sharedapp,public
# Minimum log levels, in increasing order:
# debug5, debug4, debug3, debug2, debug1,
# log, notice, warning, error, fatal, and panic
# Defaults to warning.
#min_messages: notice
# 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: postgresql
encoding: unicode
database: myapp_test
pool: 5
password:
production:
adapter: postgresql
encoding: unicode
database: myapp_production
pool: 5
password:
development:
host: localhost
test:
host: localhost

Answer 1

On most *nix servers "localhost" is handled through a Unix style socket. If you use 127.0.0.1 instead it will use TCP/IP. Try that or make sure your client and server are using the same socket address and that it is actually a usable *nix socket.
There is a configuration parameter in database.yml that lets you set the socket address, be certain that you have access to the directory as well.

Answer 2

In your config/database.yml, try adding
host: localhost
in each of your development and testing environment or more specifically looking at your existing config/database.yml shown above:
development:
adapter: postgresql
encoding: unicode
database: myapp_development
pool: 5
password:
host: localhost
test:
adapter: postgresql
encoding: unicode
database: myapp_test
pool: 5
password:
host: localhost
Hope this helps

Answer 3

I hear Heroku has made some changes to the db connection behaviour. For rails version >= 4.1 it does not overwrite your config/database.yml - it merges with it. First you need to visit https://postgres.heroku.com/databases and click on your database. You should look that parameter in the pic below
Use that variable for your production parameter like so
production:
adapter: postgresql
url: <%= ENV['HEROKU_POSTGRESQL_BLACK_URL'] %>
This is what worked for me after trying different things. I hope this helps someone.