Install ripper-tags "gem install ripper-tags" and open the user settings (File > Preferences > User Settings) and set the executable path of ripper-tags and the options to be used like the example below:
Generate the ctag file for ruby using 'CTAGS:Generate Ruby tags' command. (Press 'F1' key and type 'CTAGS:Generate Ruby tags' or the keybinding ctrl+alt+g)
After the ctag file was generated, search the symbol by select it on editor and use 'CTAGS:Search Ruby code' command. (Press 'F1' key and type 'CTAGS:Search Ruby code' or the keybinding ctrl+alt+t);
Keybindings
1. Generate ctags
Press ctrl+alt+g (cmd+alt+g on mac)
2. Search ctags
Select the words in the vscode and press ctrl+alt+t (cmd+alt+t on mac)