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

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

lib/eventos/events/track.ex

@@ -0,0 +1,23 @@
+defmodule Eventos.Events.Track do
+  use Ecto.Schema
+  import Ecto.Changeset
+  alias Eventos.Events.{Track, Event, Session}
+
+
+  schema "tracks" do
+    field :color, :string
+    field :description, :string
+    field :name, :string
+    belongs_to :event, Event
+    has_many :sessions, Session
+
+    timestamps()
+  end
+
+  @doc false
+  def changeset(%Track{} = track, attrs) do
+    track
+    |> cast(attrs, [:name, :description, :color, :event_id])
+    |> validate_required([:name, :description, :color])
+  end
+end