Error Message for Installing Postgres Gem

gistfile1.txt

[Wed Apr 17 - 23:43:17]
john@ubuntu:~/taskmail
$ gem install pg

Building native extensions.  This could take a while...
ERROR:  Error installing pg:
	ERROR: Failed to build gem native extension.

    /home/john/.rvm/rubies/ruby-2.0.0-p0/bin/ruby extconf.rb
checking for pg_config... yes
Using config values from /usr/bin/pg_config
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.h... yes
checking for PQconnectdb() in -lpq... no
checking for PQconnectdb() in -llibpq... no
checking for PQconnectdb() in -lms/libpq... no
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.

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=/home/john/.rvm/rubies/ruby-2.0.0-p0/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}/
	--with-pg-config
	--without-pg-config
	--with-pg_config
	--without-pg_config
	--with-pqlib
	--without-pqlib
	--with-libpqlib
	--without-libpqlib
	--with-ms/libpqlib
	--without-ms/libpqlib


Gem files will remain installed in /home/john/.rvm/gems/ruby-2.0.0-p0/gems/pg-0.15.1 for inspection.
Results logged to /home/john/.rvm/gems/ruby-2.0.0-p0/gems/pg-0.15.1/ext/gem_make.out