At startup, RubyMine scans your ~/.pik folder , and automatically configures SDK's for each Ruby interpreter . The detected interpreters are shown in the Ruby SDK and Gems page of the Settings dialog.
RubyMine also detects newly installed pik interpreters "on-the-fly". On reopening the Settings dialog, you will find updates in the Ruby SDK and Gems page.
All the gems, installed apart from the default gems (that come with Ruby SDK, installed via pik) are visible.