Let pins federate

- save object ids on pin, instead of activity ids
- pins federation
- removed pinned_activities field from the users table
- activityPub endpoint for user pins
- pulling remote users pins

priv/repo/migrations/20210202110641_add_pinned_objects_to_users.exs

@@ -0,0 +1,9 @@
+defmodule Pleroma.Repo.Migrations.AddPinnedObjectsToUsers do
+  use Ecto.Migration
+
+  def change do
+    alter table(:users) do
+      add(:pinned_objects, :map)
+    end
+  end
+end

priv/repo/migrations/20210203141144_add_featured_address_to_users.exs

@@ -0,0 +1,23 @@
+defmodule Pleroma.Repo.Migrations.AddFeaturedAddressToUsers do
+  use Ecto.Migration
+
+  def up do
+    alter table(:users) do
+      add(:featured_address, :string)
+    end
+
+    create(index(:users, [:featured_address]))
+
+    execute("""
+
+    update users set featured_address = concat(ap_id, '/collections/featured') where local = true and featured_address is null;
+
+    """)
+  end
+
+  def down do
+    alter table(:users) do
+      remove(:featured_address)
+    end
+  end
+end

priv/repo/migrations/20210205145000_move_pinned_activities_into_pinned_objects.exs

@@ -0,0 +1,28 @@
+defmodule Pleroma.Repo.Migrations.MovePinnedActivitiesIntoPinnedObjects do
+  use Ecto.Migration
+
+  import Ecto.Query
+
+  alias Pleroma.Repo
+  alias Pleroma.User
+
+  def up do
+    from(u in User)
+    |> select([u], {u.id, fragment("?.pinned_activities", u)})
+    |> Repo.stream()
+    |> Stream.each(fn {user_id, pinned_activities_ids} ->
+      pinned_activities = Pleroma.Activity.all_by_ids_with_object(pinned_activities_ids)
+
+      pins =
+        Map.new(pinned_activities, fn %{object: %{data: %{"id" => object_id}}} ->
+          {object_id, NaiveDateTime.utc_now()}
+        end)
+
+      from(u in User, where: u.id == ^user_id)
+      |> Repo.update_all(set: [pinned_objects: pins])
+    end)
+    |> Stream.run()
+  end
+
+  def down, do: :noop
+end

priv/repo/migrations/20210206045221_remove_pinned_activities_from_users.exs

@@ -0,0 +1,15 @@
+defmodule Pleroma.Repo.Migrations.RemovePinnedActivitiesFromUsers do
+  use Ecto.Migration
+
+  def up do
+    alter table(:users) do
+      remove(:pinned_activities)
+    end
+  end
+
+  def down do
+    alter table(:users) do
+      add(:pinned_activities, {:array, :string}, default: [])
+    end
+  end
+end