pleroma/priv/repo/migrations/20201221202251_create_hashtags.exs

defmodule Pleroma.Repo.Migrations.CreateHashtags do
  use Ecto.Migration

  def change do
    create_if_not_exists table(:hashtags) do
      add(:name, :citext, null: false)

      timestamps()
    end

    create_if_not_exists(unique_index(:hashtags, [:name]))
  end
end