feat(elixir): category managing w/ filtering &CRUD

lib/components_elixir/inventory.ex

@@ -81,6 +81,15 @@ defmodule ComponentsElixir.Inventory do
     Category.changeset(category, attrs)
   end
 
+  @doc """
+  Returns the count of components in a specific category.
+  """
+  def count_components_in_category(category_id) do
+    Component
+    |> where([c], c.category_id == ^category_id)
+    |> Repo.aggregate(:count, :id)
+  end
+
   ## Components
 
   @doc """