title: Error during installation of both PG and Bundle
body: <p>I'm in the final lesson of my first RoR tutorial and I'm being directed to open up terminal and input    <code>install bundle</code>    </p>
  
  <p>The result:</p>
  
  <pre><code>tonys-mbp:crumblr Tony-MBP$ bundle install
  Fetching gem metadata from https://rubygems.org/..........
  Resolving dependencies...
  Using rake 10.3.2
  Using i18n 0.6.11
  Using json 1.8.1
  Using minitest 5.4.2
  Using thread_safe 0.3.4
  Using tzinfo 1.2.2
  Using activesupport 4.1.6
  Using builder 3.2.2
  Using erubis 2.7.0
  Using actionview 4.1.6
  Using rack 1.5.2
  Using rack-test 0.6.2
  Using actionpack 4.1.6
  Using mime-types 2.4.1
  Using mail 2.6.1
  Using actionmailer 4.1.6
  Using activemodel 4.1.6
  Using arel 5.0.1.20140414130214
  Using activerecord 4.1.6
  Using bundler 1.7.3
  Using coffee-script-source 1.8.0
  Using execjs 2.2.1
  Using coffee-script 2.3.0
  Using thor 0.19.1
  Using railties 4.1.6
  Using coffee-rails 4.0.1
  Using hike 1.2.3
  Using multi_json 1.10.1
  Using jbuilder 2.2.2
  Using jquery-rails 3.1.2
  /Users/Tony-MBP/.rvm/gems/ruby-2.1.3/gems/bundler-1.7.3/lib/bundler.rb:302: warning: Insecure world writable dir /usr/local in PATH, mode 040777
  
  Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
  
      /Users/Tony-MBP/.rvm/rubies/ruby-2.1.3/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/Tony-MBP/.rvm/rubies/ruby-2.1.3/bin/ruby
      --with-pg
      --without-pg
      --with-pg-config
      --without-pg-config
      --with-pg_config
      --without-pg_config
      --with-pg-dir
      --without-pg-dir
      --with-pg-include
      --without-pg-include=${pg-dir}/include
      --with-pg-lib
      --without-pg-lib=${pg-dir}/lib
  
  extconf failed, exit code 1
  
  Gem files will remain installed in /Users/Tony-MBP/.rvm/gems/ruby-2.1.3/gems/pg-0.17.1 for inspection.
  Results logged to /Users/Tony-MBP/.rvm/gems/ruby-2.1.3/extensions/x86_64-darwin-13/2.1.0/pg-0.17.1/gem_make.out
  An error occurred while installing pg (0.17.1), and Bundler cannot continue.
  Make sure that `gem install pg -v '0.17.1'` succeeds before bundling.
  </code></pre>
  
  <p>So I tried installing pg so I can continue on with Bundler; however, I get this error when I input: <code>gem install pg -v '0.17.1'</code>:</p>
  
  <p>Result:</p>
  
  <pre><code>tonys-mbp:crumblr Tony-MBP$ gem install pg
  Building native extensions.  This could take a while...
  /Users/Tony-MBP/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/rubygems/ext/builder.rb:73: warning: Insecure world writable dir /usr/local in PATH, mode 040777
  ERROR:  Error installing pg:
      ERROR: Failed to build gem native extension.
  
      /Users/Tony-MBP/.rvm/rubies/ruby-2.1.3/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/Tony-MBP/.rvm/rubies/ruby-2.1.3/bin/ruby
      --with-pg
      --without-pg
      --with-pg-config
      --without-pg-config
      --with-pg_config
      --without-pg_config
      --with-pg-dir
      --without-pg-dir
      --with-pg-include
      --without-pg-include=${pg-dir}/include
      --with-pg-lib
      --without-pg-lib=${pg-dir}/lib
  
  extconf failed, exit code 1
  
  Gem files will remain installed in /Users/Tony-MBP/.rvm/gems/ruby-2.1.3/gems/pg-0.17.1 for inspection.
  Results logged to /Users/Tony-MBP/.rvm/gems/ruby-2.1.3/extensions/x86_64-darwin-13/2.1.0/pg-0.17.1/gem_make.out
  </code></pre>
  
  <p>Can anyone please help identify why both of these are failing? Thanks for helping out a complete newb in his developer infancy.</p>
  
  <p>Edit:</p>
  
  <p>After trying the suggested code from @Lidan, this is what I get:</p>
  
  <pre><code>Building native extensions with: '--with-pg-config=/Applications/Postgres.app/Contents/MacOS/bin/pg_config'
      This could take a while...
      /Users/Tony-MBP/.rvm/rubies/ruby-2.1.3/lib/ruby/2.1.0/rubygems/ext/builder.rb:73: warning: Insecure world writable dir /usr/local in PATH, mode 040777
      ERROR:  Error installing pg:
          ERROR: Failed to build gem native extension.
  </code></pre>