Add Ruby code preview to website

I want to see how it looks with Ruby source code.


Feel free to use this snippet:
```rb
class Person
attr_accessor :name, :age

def initialize(name, age)
@name = name
@age += age
end

def ==(other)
@name == other.name && @age == other.age
end

def <=>(other)
@age <=> other.age
end

def !~(other)
@name !~ other.name || @age != other.age
end

def =~(other)
@name =~ other.name && @age == other.age
end

def <<(other)
@name << other.name
end

def >>(other)
@age >> other.age
end

def **(other)
@age ** other.age
end

def &&(other)
@name && other.name && @age && other.age
end

def ||(other)
@name || other.name || @age || other.age
end
end

alice = Person.new("Alice", 30)
bob = Person.new("Bob", 35)

puts alice == bob # => false
puts alice <=> bob # => -1
puts alice !~ bob # => true
puts alice =~ bob # => false
puts alice << bob # => "AliceBob"
puts alice >> bob # => 30
puts alice ** bob # => 9000000000000000
puts alice && bob # => true
puts alice || bob # => true
```

Start by locating the website code that assembles the existing code previews and compare how other source languages are represented. Add the supplied Ruby snippet where appropriate, then verify that the website renders the Ruby source correctly.

Written by the indexing model from the issue text.