Run coveralls only on CircleCI

config.yml

    - run:
          name: Run Golang Tests
          command: |
            GOPATH=$GOPATH:"${SYNQ_DIR}"/"${REPO}"/vendor overalls -project=github.com/SYNQfm/"${REPO}" -covermode=atomic -debug -ignore=.git,.github,.circleci,vendor,sql,sample -- -race -v
            if [ -z ${COVERALLS_TOKEN} ]; then
              echo "coveralls token isn't set, skipping"
            else
              goveralls -coverprofile="${SYNQ_DIR}"/"${REPO}"/overalls.coverprofile -service circle-ci -repotoken "${COVERALLS_TOKEN}"
            fi