Can't install mysql2 gem on macOS Sierra

Question

I\'m setting up my development environment in the new macOS Sierra .

First of all, I installed Rbenv, Ruby (2.3.1)

Answer 1

Lots of great answers, I was able to combine them into this:

gem install mysql2 --source 'https://rubygems.org/' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include

because I was not comfortable with bundle config