Change models, new migrations, fix front and make tests work

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

priv/repo/migrations/20180110165029_guardiandb.exs

@@ -0,0 +1,17 @@
+defmodule Eventos.Repo.Migrations.Guardian.DB do
+  use Ecto.Migration
+
+  def change do
+    create table(:guardian_tokens, primary_key: false) do
+      add(:jti, :string, primary_key: true)
+      add(:aud, :string, primary_key: true)
+      add(:typ, :string)
+      add(:iss, :string)
+      add(:sub, :string)
+      add(:exp, :bigint)
+      add(:jwt, :text)
+      add(:claims, :map)
+      timestamps()
+    end
+  end
+end