Do object insertion through Cachex

So we don't flood our postgres logs with errors. Should also make things
slightly faster.

test/object_test.exs

@@ -57,4 +57,32 @@ defmodule Pleroma.ObjectTest do
       assert cached_object.data["type"] == "Tombstone"
     end
   end
+
+  describe "insert_or_get" do
+    test "inserting the same object twice (by id) just returns the original object" do
+      data = %{data: %{"id" => Ecto.UUID.generate()}}
+      cng = Object.change(%Object{}, data)
+      {:ok, object} = Object.insert_or_get(cng)
+      {:ok, second_object} = Object.insert_or_get(cng)
+
+      Cachex.clear(:object_cache)
+      {:ok, third_object} = Object.insert_or_get(cng)
+
+      assert object == second_object
+      assert object == third_object
+    end
+  end
+
+  describe "create" do
+    test "inserts an object for a given data set" do
+      data = %{"id" => Ecto.UUID.generate()}
+
+      {:ok, object} = Object.create(data)
+      assert object.data["id"] == data["id"]
+
+      # Works when doing it twice.
+      {:ok, object} = Object.create(data)
+      assert object.data["id"] == data["id"]
+    end
+  end
 end