Merge branch 'refactor/db-not-null-constraints-for-user_invite_tokens' into 'develop'

Add NOT NULL constraints for user_invite_tokens table

See merge request pleroma/pleroma!1909

priv/repo/migrations/20191026191826_set_not_null_for_user_invite_tokens.exs

+defmodule Pleroma.Repo.Migrations.SetNotNullForUserInviteTokens do
+  use Ecto.Migration
+
+  # modify/3 function will require index recreation, so using execute/1 instead
+
+  def up do
+    execute("ALTER TABLE user_invite_tokens
+    ALTER COLUMN used SET NOT NULL,
+    ALTER COLUMN uses SET NOT NULL,
+    ALTER COLUMN invite_type SET NOT NULL")
+  end
+
+  def down do
+    execute("ALTER TABLE user_invite_tokens
+    ALTER COLUMN used DROP NOT NULL,
+    ALTER COLUMN uses DROP NOT NULL,
+    ALTER COLUMN invite_type DROP NOT NULL")
+  end
+end