@spec add_alias(
  Igniter.t(),
  atom() | String.t(),
  String.t() | [String.t()],
  opts :: Keyword.t()
) :: Igniter.t()

Adds an alias to the mix.exs file

Options

• :if_exists - How to alter the alias if it already exists. Options are:
  • :ignore - Do nothing if the alias already exists. This is the default.
  • :prepend - Add the new alias to the beginning of the list of aliases.
  • :append - Add the new alias to the end of the list of aliases.
  • :warn - Print a warning if the alias already exists.