Error in Installing pg

Some time when you do bundle install, on installing pg gem you face an error of following type:
C:/Ruby/bin/ruby.exe 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
–without-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=C:/Ruby/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 C:/Ruby/lib/ruby/gems/1.8/gems/pg-0.10.1 for
inspection.
Results logged to C:/Ruby/lib/ruby/gems/1.8/gems/pg-0.10.1/ext/gem_make.out

to resolve it just run this command:

sudo apt-get install libpq-dev