add some exercises

exercises/done/gecko_01.rb

@@ -0,0 +1,32 @@
+#!/usr/bin/env ruby
+
+class Gecko
+  def initialize(name)
+    @name = name
+    @meals = []
+  end
+
+  def eat(prey)
+    @meals << prey
+  end
+
+  def display_meals
+    puts "#{@name} a mangé :"
+
+    @meals.each do |prey|
+      puts "- #{prey}"
+    end
+
+    puts
+    suffix = @meals.length == 1 ? "proie" : "proies"
+    puts "Total : #{@meals.length} #{suffix}"
+  end
+end
+
+delta = Gecko.new("Delta")
+
+delta.eat("dubia")
+delta.eat("ver de farine")
+delta.eat("cloporte")
+
+delta.display_meals