Returns a entity.

## Examples

iex> Red.entity(1) %Red.Entity{id: 1}

iex> Red.entity({:user, 42}) %Red.Entity{class: :user, id: 42}

iex> Red.entity(“user#42”) %Red.Entity{class: “user”, id: “42”}

iex> Red.entity(“key”) %Red.Entity{id: “key”}

iex> Red.entity(user: 42) %Red.Entity{class: :user, id: 42}

iex> %Red.Entity{id: 1} |> Red.entity %Red.Entity{id: 1}

See Red.Key.build/1.

Returns a relation.

## Examples

iex> “user#42” |> Red.rel(:follow) %Red.Rel{

name: :follow,
direction: :out,
entity: %Red.Entity{class: "user", id: "42"}

}

iex> {:user, 42} |> Red.rel(:follow, :in) %Red.Rel{

name: :follow,
direction: :in,
entity: %Red.Entity{class: :user, id: 42}

}