Ruby is a high-level, interpreted programming language renowned for its simplicity and efficiency. Established in the mid-90s by Yukihiro "Matz" Matsumoto, Ruby combines parts of different languages (Perl, Smalltalk, Eiffel, Ada, Basic) to provide a balanced, flexible language that emphasizes the happiness and productivity of programmers. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming, and has a dynamic type system and automatic memory management.

As a Ruby programmer, you'll be expected to create, design, and modify computer apps by converting project specifications and statements of issues and procedures into logical, step-by-step instructions that can be executed by a computer. You may also be responsible for testing, debugging, and maintaining your programs.

Understanding Ruby's syntax and rules is vital when working in many tech spaces, including web development where Ruby on Rails, a popular web-application framework, is commonly used. Employers looking for Ruby skills are often seeking individuals with a strong understanding of programming principles, efficient coding abilities, as well as problem-solving skills.

Associated foundational skills for mastering Ruby include an understanding of other programming languages such as Python or JavaScript, which would help in grasping Ruby's object-oriented aspects as well as its syntax. Familiarity with HTML and CSS, the core technologies used for building web pages, would also serve as a good base, especially for those interested in Ruby on Rails. Furthermore, a knowledge of SQL would be beneficial as it would aid in understanding databases, an essential part of many web applications.

Lastly, mastering Ruby goes beyond knowing its syntax and rules. Rubyists are part of an active community that values 'programmer happiness' and following the principles of good software design. Hence, maintaining good coding practices, participating in code reviews, and involving oneself in the Ruby community would be helpful in not just learning Ruby, but also in excelling at it.