Add 'About Ruby' unit

Author: paulgoetze

1_Introduction/1_About_Ruby/solution_spec.rb

@@ -0,0 +1,46 @@
+# About Ruby
+
+---
+
+*You will learn:*
+- some facts about Ruby
+- what a Ruby file looks like
+- how to use the interactive Ruby console
+
+---
+
+## Ruby is...
+
+`  " A dynamic, open source programming language with a focus on`
+`    simplicity and productivity. It has an elegant syntax that`
+`    is natural to read and easy to write. "`
+
+as the official Ruby page (https://www.ruby-lang.org) describes it.
+
+It was designed and built in the mid-90s by *Yukihiro "Matz" Matsumoto* in Japan.
+
+Ruby is a cross platform interpreted language with a dynamic type system and
+automatic memory management. Its development was inspired by multiple other
+programming languages, such as Perl, Smalltalk, Eiffel, Ada, and Lisp.
+
+There are several different implementations of Ruby.
+The *MRI* (Matz Ruby Implementation) or *CRuby* is the reference implementation.
+Other implementations are *JRuby*, *Rubinius*, *MacRuby*, *mruby*, *IronRuby*,...
+
+Ruby is often used to build web applications, due to the mature *Ruby on Rails*
+and *Sinatra* frameworks. Nevertheless it can be applied to all kinds of use
+cases, from prototyping, to scientific computation, to command line interfaces
+and desktop apps (Daigaku is also fully written in Ruby :) ).
+
+## Naming Ruby files
+
+Source code files for Ruby have a `.rb` extension and are usually named with
+lowercase words, which are - if necessary - joined by an underscore:
+
+e.g. `student.rb`, `multiple_words.rb`, `even_more_words.rb`.
+
+## The interactive Ruby console
+
+If you open a new tab in your terminal and enter `irb`, you will start the
+*interactive Ruby* console. The irb is a useful tool for rapidly trying out
+ruby code. You can quit the irb again by entering `exit`. Give it a try!