Add koans for floats, rename to numbers koans, reposition on the list

lib/koans/08_maps.ex

@@ -1,59 +0,0 @@
-defmodule Maps do
-  use Koans
-
-  @intro "Maps"
-
-  @person %{
-    first_name: "Jon",
-    last_name: "Snow",
-    age: 27,
-  }
-
-  koan "Maps represent structured data, like a person" do
-    assert @person == %{first_name: ___,
-                        last_name: "Snow",
-                        age: 27 }
-  end
-
-  koan "Fetching a value returns a tuple with ok when it exists" do
-    assert Map.fetch(@person, :age) == ___
-  end
-
-  koan "Or the atom :error when it doesn't" do
-    assert Map.fetch(@person, :family) == ___
-  end
-
-  koan "Extending a map is as simple as adding a new pair" do
-    person_with_hobby = Map.put(@person, :hobby, "Kayaking")
-    assert Map.fetch(person_with_hobby, :hobby) == ___
-  end
-
-  koan "Put can also overwrite existing values" do
-    older_person = Map.put(@person, :age, 37)
-    assert Map.fetch(older_person, :age) == ___
-  end
-
-  koan "Or you can use some syntactic sugar for existing elements" do
-    younger_person = %{@person | age: 16}
-    assert Map.fetch(younger_person, :age) == ___
-  end
-
-  koan "Can remove pairs by key" do
-    without_age = Map.delete(@person, :age)
-    assert Map.has_key?(without_age, :age) == ___
-  end
-
-  koan "Can merge maps" do
-    assert Map.merge(%{first_name: "Jon"}, %{last_name: "Snow"}) == ___
-  end
-
-  koan "When merging, the last map wins" do
-    merged = Map.merge(@person, %{last_name: "Baratheon"})
-    assert Map.fetch(merged, :last_name) == ___
-  end
-
-  koan "You can also select sub-maps out of a larger map" do
-    initial = %{first_name: "Jon", last_name: "Snow", age: 15}
-    assert Map.take(initial, [:first_name, :last_name]) == ___
-  end
-end