Error installing mysql2: Failed to build gem native extension

you want running bundle install or gem install mysql2 it gives the following error:

Error installing mysql2: ERROR: Failed to build gem native extension.

How to fix this and successfully install mysql2?

On Ubuntu/Debian and other distributions using aptitude:

sudo apt-get install libmysql-ruby libmysqlclient-dev
Package libmysql-ruby has been phased out and replaced by ruby-mysql. This is where I found the solution.

If the above command doesn't work because libmysql-ruby cannot be found, the following should be sufficient:

sudo apt-get install libmysqlclient-dev
On Red Hat/CentOS and other distributions using yum:

sudo yum install mysql-devel
On Mac OS X with Homebrew:

brew install mysql