I just submitted my own RSS feed using curl and jq, by doing this:

  $ RSS_URL="https://www.grepular.com/rss"
  $ FEEDI_TOKEN=$(curl -sX POST https://feedi.me/tokens \
    | jq -r '.data.attributes.key')
  $ curl -X POST https://feedi.me/feeds \
    -H "Authorization: Token $FEEDI_TOKEN" \
    -H "Content-Type: application/json" \
    -H "Accept: application/json" \
    -d "{\"url\":\"$RSS_URL\"}"

As per the API docs at https://github.com/davidesantangelo/feedi