Check gofmt during CI build

.circleci/check-gofmt

+#!/bin/bash
+
+result="$(gofmt -e -s -l . 2>&1 | grep -v '^vendor/' )"
+if [ -n "$result" ]; then
+  echo "Go code is not formatted, run 'gofmt -e -s -w .'" >&2
+  echo "$result"
+  exit 1
+else
+  echo "Go code is formatted well"
+fi

.circleci/config.yml

@@ -18,3 +18,4 @@ jobs:
       - run: go test -v -cover -coverprofile=coverage.out ./...
       - run: goveralls -coverprofile=coverage.out -service=circle-ci -repotoken=$COVERALLS_TOKEN
       - run: .circleci/build-examples
+      - run: .circleci/check-gofmt