Bundle install error 'error occurred while installing json (1.7.3)'
One part of the problem is due to a change in rb_str_new.
This is a related issue on their GitHub page: https://github.com/flori/json/issues/229
As I understand it, the contributors decided to not fix this since it works as it should in json 1.8.3. It's recommended that you upgrade to that version. The json gem has a very stable API so backwards compatibility is usually not an issue.
If you are using bundler you should go to your Gemfile and change version of json to 1.8.3 or higher using gem 'json', '>=1.8.3'.
In Gemfile you add
gem 'json', '1.7.3'
after that,
bundle install