pg not installing

gistfile1.txt

Fetching gem metadata from http://rubygems.org/.......
Installing rake (0.9.2.2) 
Installing multi_json (1.0.4) 
Installing activesupport (3.1.3) 
Installing builder (3.0.0) 
Installing i18n (0.6.0) 
Installing activemodel (3.1.3) 
Installing erubis (2.7.0) 
Installing rack (1.3.5) 
Installing rack-cache (1.1) 
Installing rack-mount (0.8.3) 
Installing rack-test (0.6.1) 
Installing hike (1.2.1) 
Installing tilt (1.3.3) 
Installing sprockets (2.0.3) 
Installing actionpack (3.1.3) 
Installing mime-types (1.17.2) 
Installing polyglot (0.3.3) 
Installing treetop (1.4.10) 
Installing mail (2.3.0) 
Installing actionmailer (3.1.3) 
Installing arel (2.2.1) 
Installing tzinfo (0.3.31) 
Installing activerecord (3.1.3) 
Installing activeresource (3.1.3) 
Installing ansi (1.4.1) 
Installing chunky_png (1.2.5) 
Installing coffee-script-source (1.2.0) 
Installing execjs (1.2.13) 
Installing coffee-script (2.2.0) 
Installing rack-ssl (1.3.2) 
Installing json (1.6.4) with native extensions 
Installing rdoc (3.12) 
Installing thor (0.14.6) 
Installing railties (3.1.3) 
Installing coffee-rails (3.1.1) 
Installing fssm (0.2.7) 
Installing sass (3.1.12) 
Installing compass (0.12.alpha.3) 
Installing haml (3.1.4) 
Installing haml-rails (0.3.4) 
Installing jquery-rails (1.0.19) 
Installing rake-compiler (0.7.9) 
Installing pg (0.12.0) with native extensions Unfortunately, a fatal error has occurred. Please report this error to the Bundler issue tracker at https://github.com/carlhuda/bundler/issues so that we can fix it. Thanks!
/Users/omar/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:552:in `rescue in block in build_extensions': ERROR: Failed to build gem native extension. (Gem::Installer::ExtensionBuildError)

        /Users/omar/.rvm/rubies/ruby-1.9.2-p290/bin/ruby extconf.rb 
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
 --with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** 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.

Provided configuration options:
	--with-opt-dir
	--with-opt-include
	--without-opt-include=${opt-dir}/include
	--with-opt-lib
	--without-opt-lib=${opt-dir}/lib
	--with-make-prog
	--without-make-prog
	--srcdir=.
	--curdir
	--ruby=/Users/omar/.rvm/rubies/ruby-1.9.2-p290/bin/ruby
	--with-pg
	--without-pg
	--with-pg-dir
	--without-pg-dir
	--with-pg-include
	--without-pg-include=${pg-dir}/include
	--with-pg-lib
	--without-pg-lib=${pg-dir}/lib
	--with-pg-config
	--without-pg-config
	--with-pg_config
	--without-pg_config


Gem files will remain installed in /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/pg-0.12.0 for inspection.
Results logged to /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/pg-0.12.0/ext/gem_make.out
	from /Users/omar/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:530:in `block in build_extensions'
	from /Users/omar/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:505:in `each'
	from /Users/omar/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:505:in `build_extensions'
	from /Users/omar/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:180:in `install'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/source.rb:90:in `block in install'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/rubygems_integration.rb:82:in `preserve_paths'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/source.rb:89:in `install'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/installer.rb:73:in `block in install_gem_from_spec'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/rubygems_integration.rb:97:in `with_build_args'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/installer.rb:72:in `install_gem_from_spec'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/installer.rb:56:in `block in run'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/installer.rb:55:in `run'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/installer.rb:12:in `install'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/cli.rb:220:in `install'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/vendor/thor/task.rb:22:in `run'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/vendor/thor.rb:263:in `dispatch'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/lib/bundler/vendor/thor/base.rb:386:in `start'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/gems/bundler-1.1.0/bin/bundle:13:in `<top (required)>'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/bin/bundle:19:in `load'
	from /Users/omar/.rvm/gems/ruby-1.9.2-p290/bin/bundle:19:in `<main>'