The task "release" could not be found - edeliver didn't put /rel folder to server

Hi! I’m trying to deploy Phoenix 1.4 app (elixir 1.7.4, erlang 21.1.1) to ubuntu 18.04 using this Digital Ocean tutorial with edeliver and distillery. I use asdf as version manager.

Locally releases builds just fine (by MIX_ENV="prod" mix release).

But on my Ubuntu server I got ** (Mix) The task "release" could not be found
I realize, that there is no rel/ folder on prod server in ~/app_build/ folder, so mix can’t find config.exs and can’t start release task.
What should I do with edeliver (or with anything) to convince him to put that folder to server?

$ mix edeliver build release          

BUILDING RELEASE OF MY_APP APP ON BUILD HOST

-----> Authorizing hosts
-----> Ensuring hosts are ready to accept git pushes
-----> Pushing new commits with git to: deploy@<my_domen.com>
-----> Resetting remote hosts to 5b0466a25cc4050a062942e2108db21fbe3a2434
-----> Cleaning generated files from last build
-----> Fetching / Updating dependencies
-----> Compiling sources
-----> Generating release
using mix to generate release
** (Mix) The task "release" could not be found

A remote command failed on:

  deploy@<my_domen.com>

Output of the command is shown above and the command executed
on that host is printed below for debugging purposes:

FAILED with exit status 1:

    [ -f ~/.profile ] && source ~/.profile
    set -e
    cd /home/deploy/app_build
    if [ "mix" = "rebar" ]; then
      echo "using rebar to generate release"
      ./rebar   -f generate
    elif [ "mix" = "relx" ]; then
      echo "using relx to generate release"
      ./relx release
    elif [ "mix" = "mix" ]; then
      echo "using mix to generate release"
      MIX_ENV="prod" LINK_SYS_CONFIG="" LINK_VM_ARGS="" APP="my_app" AUTO_VERSION="" BRANCH="master" SKIP_RELUP_MODIFICATIONS="" RELUP_MODIFICATION_MODULE="" USING_DISTILLERY="true" mix  release --verbose --env="prod" --name="my_app"
    fi

Here my files:

• /mix.exs
• /.deliver/config
• /rel/config.exs