See web help, sections:
RubyMine / Concepts / Project
RubyMine / Concepts / Contents
RubyMine / Concepts / Scope
RubyMine / Concepts / Running and Debugging
RubyMine / Concepts / Running and Debugging / Breakpoints
RubyMine / Concepts / Templates
RubyMine / Concepts / Testing Support
RubyMine / Procedures / Configuring Projects / Configuring Content Roots
RubyMine / Procedures / Configuring Projects / Configuring Folders Within the Content Root
RubyMine / Procedures / Creating and Managing Projects / Opening, Reopening and Closing Project
RubyMine / Procedures / Advanced Editing Procedures / Auto-Completing Code / Completing Path
RubyMine / Procedures / Advanced Editing Procedures / Creating Code By Template / Creating Code Constructs by Live Templates
RubyMine / Procedures / Advanced Editing Procedures / Generating Code / Commenting and Uncommenting Blocks of Code
RubyMine / Procedures / Advanced Editing Procedures / Genera
RubyMine / Procedures / Inspecting Source Code / Accessing Inspection Profiles Settingsting Code / Surrounding Blocks of Code with Language
RubyMine / Procedures / Inspecting Source Code / Configuring Inspection SeveritiesConstructs
RubyMine / Procedures / Analyzing Applications / Analyzing External Stacktraces
RubyMine / Procedures / Navigating Through the Source Code / Navigating With Structure Views
RubyMine / Procedures / Viewing Reference Information
RubyMine / Procedures / Navigating Through the Source Code / Navigating With Structure Views
RubyMine / Procedures / Running / Creating and Editing Run/Debug Configurations
RubyMine / Procedures / Running / Running Applications
RubyMine / Procedures / Running / Running Rails Server
RubyMine / Procedures / Debugging
RubyMine / Procedures / Debugging / Using Breakpoints

and more

Issue was resolved