"sqlite3.h" missing when pushing Rails app to Heroku

Heroku uses postgresql so you want to remove sqlite3 or move it into a development group in your Gemfile.

Check you Gemfile.lock for any other gems that may have dependencies on sqlite3, as this can also cause problems.

gem 'sqlite3', :group => [:development, :test]
group :production do
  gem 'pg'
end

1. edit Gemfile as above
2. remove Gemfile.lock
3. run bundle install --without production
4. git add .
5. git commit -am "bundle updating sqlite3"
6. git push heroku master

What happened to me was, I was following along the Heroku tutorial and when I used git push heroku master it was pushing from my latest Git commit (obviously!)

What I forgot was that in the eyes of Git, I was still using sqlite in the gemfile! Silly me!

So I used git add . followed by a git commit -m "Changed to Postgres." so Git knew about these changes. Pushing after that worked fine for me.

I had a similar problem and I wasn't even using sqlite3 for anything but after removing it from the gem file I still got that error

what solved it for me was a commit command

git commit -am 

that I found on this tutorial