Mojave: Ruby and Rails - 
Setting up Ruby / Rails can be quite a challenge, in this episode we'll walk you through the process so you can get up and running with ruby and rails as fast as possible. Make sure you have asdf-vm installed if you haven't check out our previous episode
Installing ASDF Ruby Plugin
We'll need to install the asdf plugin for ruby.
asdf plugin-add ruby
This should setup the ruby plugin for us.
We can list out the different version of ruby by typing
asdf list-all ruby
Let's install ruby version 2.5.1
asdf install ruby 2.5.1
This will download and compile ruby for us.
We'll need to do a reshim using asdf and use the version we want to use.
asdf reshim ruby 2.5.1
Let's set the version
asdf global ruby 2.5.1
This will set ruby 2.5.1 as the global default version on our system. You can also set the version locally on a per project basis using
# in the project direcory
asdf local ruby 2.5.1
Now that we've changed the ruby version launch a new terminal session (new window or new tab cmd + t ).
Verifying our Setup
We can verify our ruby version by typing
It should show 2.5.1 in the output.
Adding Shims to the $PATH
We need to add the ruby shims to the path by modifying the ~/.zshrc . You can type which gem and it will show you the path of the shims copy /usr/local/opt/asdf/shims and add
# in ~/.zshrc
Now we can run source ~/.zshrc
This will add the shims to the path which means we'll able to run ruby bins without specifying the path.
We can now finally install rails
gem install rails
Once this is done we can launch a new tab or open a new session to re-initialize the environment
Generating a new Rails App
Once everything is setup we can simply generate a new rails app
rails new example
This will generate a new project called example . Go into the directory and launch rails
That's it! We're all done simply browse to localhost:3000 to hit our rails app and verify that everything is working.