Installing pg gem on ubuntu

Question

I'm developing a rails app using sqlite3. I want to push it to Heroku. In Heroku tutorial it says that I have to first change:

gem 'sqlite3'

to

gem 'pg'

and run

bundle install

I got this error:

 Installing pg (0.14.1) with native extensions 
 Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
 ...
 Can't find the PostgreSQL client library (libpq)
 *** extconf.rb failed ***
 Could not create Makefile due to some reason, probably lack of
 necessary libraries and/or headers.  Check the mkmf.log file for more
 details.  You may need configuration options.
 ...

next I tried the solution proposed here :

 running gem install pg -- --with-pg-config= /usr/bin/pg_config

I also tried running:

 sudo apt-get install postgresql
 sudo apt-get install libpq-dev

and

 gem install pg

works fine..

But

 bundle install

still gives me the same error

Note: I'm using rvm

Answer 1

did you try

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

group :production do
  gem 'pg'
end

in your gemfile so that you can use sqlite in development and when you push to heroku as production it will be pg.

Answer 2

Change your gemfile to the following:

gem 'sqlite3', :group => :development
gem 'pg', :group => :production

This way you will use SQL locally in development. Heroku will ignore the sqlite gem, and use Postgres instead.