User search: Make uri matches case insensitive.

priv/repo/migrations/20200925065249_make_user_ids_ci.exs

@@ -0,0 +1,19 @@
+defmodule Pleroma.Repo.Migrations.MakeUserIdsCI do
+  use Ecto.Migration
+
+  def up do
+    alter table(:users) do
+      modify(:uri, :citext)
+    end
+
+    create(unique_index(:users, :uri))
+  end
+
+  def don do
+    drop(unique_index(:users, :uri))
+
+    alter table(:users) do
+      modify(:uri, :text)
+    end
+  end
+end