Ruby on rails git push heroku master issue with sqlite3 - ruby-on-rails

Question

i know this is an old issue and i saw many questions related to the same issue. I still keep getting the same error. I followed the solutions and changed my gemfile accordingly but i still get the same issue. Im using ubuntu.
Below is my issue when i run git push heroku master as said in Michael Hartl's tutorial:
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=/usr/local/bin/ruby
--with-sqlite3-dir
--without-sqlite3-dir
--with-sqlite3-include
--without-sqlite3-include=${sqlite3-dir}/include
--with-sqlite3-lib
--without-sqlite3-lib=${sqlite3-dir}/lib
--enable-local
--disable-local
Gem files will remain installed in /tmp/build_t7ck4nq1x4dd/vendor/bundle/ruby/1.9.1/gems/sqlite3-1.3.6 for inspection.
Results logged to /tmp/build_t7ck4nq1x4dd/vendor/bundle/ruby/1.9.1/gems/sqlite3-1.3.6/ext/sqlite3/gem_make.out
An error occurred while installing sqlite3 (1.3.6), and Bundler cannot continue.
Make sure that `gem install sqlite3 -v '1.3.6'` succeeds before bundling.
!
! Failed to install gems via Bundler.
!
! Heroku push rejected, failed to compile Ruby/rails app
To git#heroku.com:pure-dusk-8885.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'git#heroku.com:pure-dusk-8885.git'
Here is my Gemfile
source 'https://rubygems.org'
gem 'rails', '3.2.5'
# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'
group :production do
gem 'pg'
end
group :development, :test do
gem 'sqlite3'
gem 'taps'
gem 'rvm'
end
# Gems used only for assets and not required
# in production environments by default.
group :assets do
gem 'sass-rails', '~> 3.2.3'
gem 'coffee-rails', '~> 3.2.1'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', :platforms => :ruby
gem 'uglifier', '>= 1.0.3'
end
gem 'jquery-rails'
# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'
# To use Jbuilder templates for JSON
# gem 'jbuilder'
# Use unicorn as the app server
# gem 'unicorn'
# Deploy with Capistrano
# gem 'capistrano'
# To use debugger
# gem 'debugger'
Please help

Answer 1

As Ryan Bigg said you should have the same environment in both development and production so you don't have surprises later when you deploy to production.
But if you don't care about that and want to keep with sqlite I think you only need to run bundle install. I guess you changed your GemFile but didn't ran bundle install.

Answer 2

Remove sqlite3 from your Gemfile. Develop using only the pg gem, so that you're developing on exactly the same database system as what you're deploying to.
If you're not doing this, then you may run into problems when you transition between the two database systems.