Lint code before running build

.gitlab-ci.yml

 image: golang:1.9
 
 stages:
+  - check
   - build
   - test
 
@@ -10,6 +11,14 @@ before_script:
   - ln -sv ${CI_PROJECT_DIR} /go/src/git.zacharyseguin.ca/${CI_PROJECT_PATH}
   - cd /go/src/git.zacharyseguin.ca/${CI_PROJECT_PATH}
 
+go lint:
+  stage: check
+  before_script:
+    - go get gopkg.in/alecthomas/gometalinter.v1
+    - gometalinter.v1 --install
+  script:
+    - gometalinter.v1 --exclude=vendor --disable-all --enable=golint ./...
+
 go build:
   stage: build
   script:

track/segment_type.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 )
 
+// SegmentType is the type of track segment.
 type SegmentType int
 
 const (