Ruby is a dynamic, reflective, object-oriented, general-purpose programming language. It was designed and developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan.

According to its authors, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, and Lisp. It supports multiple programming paradigms, including functional, object-oriented, and imperative. It also has a dynamic type system and automatic memory management.

(Wikipedia)

Summary:

• Code quality metrics
• Dependency management
• Static code analysis with Brakeman
• Tainting and restricted code execution
• Dangerous methods
• Symbols
• Serialization in Ruby
• Regular expressions
• Object.send
• SSL in Ruby
• Authentication and session management
• Authorization and user management
• Common attacks and mitigations
• Client-side security
• Application and server configuration and hardening