Move sigils to later in the lessons

While doing this, I also discovered that
there is also a reference to lists in numbers, but
that might a bit easier for someone to grasp, given
the hint that the koan gives, and the output they
see when they run it.

lib/koans/05_tuples.ex

@@ -0,0 +1,37 @@
+defmodule Tuples do
+  use Koans
+
+  @intro "Tuples"
+
+  koan "Tuples can contain different things" do
+    assert {:a, 1, "hi"} == ___
+  end
+
+  koan "Tuples have a size" do
+    assert tuple_size({:a, :b, :c}) == ___
+  end
+
+  koan "You can pull out individual elements" do
+    assert elem({:a, "hi"}, 1) == ___
+  end
+
+  koan "You can change individual elements of a tuple" do
+    assert put_elem({:a, "hi"}, 1, "bye") == ___
+  end
+
+  koan "You can also simply extend a tuple with new stuff" do
+    assert Tuple.insert_at({:a, "hi"}, 1, :new_thing) == ___
+  end
+
+  koan "Add things at the end" do
+    assert Tuple.append({"Huey", "Dewey"}, "Louie") == ___
+  end
+
+  koan "Or remove them" do
+    assert Tuple.delete_at({:this, :is, :not, :awesome}, 2) == ___
+  end
+
+  koan "Turn it into a list in case you need it" do
+    assert Tuple.to_list({:this, :can, :be, :a, :list}) == ___
+  end
+end