Add a method to create an Link using a generator.

lib/link_shortener/links.ex

@@ -4,6 +4,7 @@ defmodule LinkShortener.Links do
   import Ecto.Query
   alias LinkShortener.Repo
   alias LinkShortener.Links
+  alias LinkShortener.Generators.SafeString
 
   schema "links" do
     field :name, :string
@@ -23,6 +24,11 @@ defmodule LinkShortener.Links do
 
   def new_one(), do: Links.changeset(%Links{})
 
+  def create_one(attrs, length \\ 10, generator \\ SafeString) do
+    shorten = generator.generate(length)
+    insert_one(Map.put(attrs, :shorten, shorten))
+  end
+
   def insert_one(attrs) do
     %Links{}
     |> Links.changeset(attrs)