no AdditiveGroup trait in ark_ec library, but it is used in elgamal module

[ash370]

When I use elgamal module，I find error in code

use ark_ec::{AdditiveGroup, CurveGroup};

there is not AdditiveGroup trait in ark_ec library.
What can I do to solve this problem？

[storojs72]

Confirm, trying to build from rev='fc1c9491c62ce51edf4f0b4e2ab270b85d0150ab':

Compiling ark-crypto-primitives v0.4.0 (https://github.com/arkworks-rs/crypto-primitives?rev=fc1c9491c62ce51edf4f0b4e2ab270b85d0150ab#fc1c9491)
error[E0432]: unresolved import `ark_ec::AdditiveGroup`

[mmagician]

You will need to patch, like here, or use the 0.5.0-alpha release.