Added behaviour

lib/predictions/repo/behaviour.ex

@@ -0,0 +1,19 @@
+defmodule Predictions.Repo.Behaviour do
+  @moduledoc """
+  Behavior for an API client for fetching prediction data.
+  """
+
+  alias RoutePatterns.RoutePattern
+  alias Routes.Route
+  alias Stops.Stop
+
+  @doc """
+  Return predictions for given params
+  """
+  @callback all(Keyword.t()) :: [Predictions.Prediction.t()] | []
+
+  @doc """
+  Return predictions for give prarams ignoring the cache
+  """
+  @callback all_no_cache(Keyword.t()) :: [Predictions.Prediction.t()] | []
+end