Add git commit to build

.drone.yml

@@ -8,7 +8,7 @@ steps:
   commands:
   - go get github.com/bwmarrin/discordgo
   - go vet -v
-  - go build
+  - go build -ldflags "-X main.gitCommit=$(git rev-parse --short HEAD)"
 - name: Run
   image: golang
   environment: