Fix migration

priv/repo/migrations/20170522160642_case_insensivtivity.exs

@@ -3,17 +3,23 @@ defmodule Pleroma.Repo.Migrations.CaseInsensivtivity do
 
   def up do
     execute("create extension if not exists citext")
+
+    drop_if_exists(index(:users, [:email]))
+
     alter table(:users) do
-      modify :email, :citext
-      modify :nickname, :citext
+      modify(:email, :citext)
+      modify(:nickname, :citext)
     end
+
+    create_if_not_exists(index(:users, [:email]))
   end
 
   def down do
     alter table(:users) do
-      modify :email, :string
-      modify :nickname, :string
+      modify(:email, :string)
+      modify(:nickname, :string)
     end
+
     execute("drop extension if exists citext")
   end
 end