Could not find gem 'mysql2 (< 0.5, >= 0.3.18)' in any of the gem sources listed in your Gemfile

Question

I got below error while creating new rails application. I ran bundle install but didn't work it.

Could not find gem 'mysql2 (< 0.5, >= 0.3.18)' in any of the gem sources listed in your Gemfile.

Gemfile

git_source(:github) do |repo_name|
  repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
  "https://github.com/#{repo_name}.git"
end


# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.1.5'
# Use mysql as the database for Active Record
gem 'mysql2', '>= 0.3.18', '< 0.5'
# Use Puma as the app server
gem 'puma', '~> 3.7'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

Answer 1

Try to delete your Gemfile.lock and run bundle install again

rm Gemfile.lock
bundle install

Answer 2

When I tried with what you have provided, I was able to install mysql2 gem. Give it a go with this one (change or install the ruby version first) and let me know if it didn't change anything:

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.5.0'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.2.0.rc1'
# Use Puma as the app server
gem 'puma', '~> 3.11'
# Use mysql as the database for Active Record
gem 'mysql2', '>= 0.3.18', '< 0.5'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'mini_racer', platforms: :ruby