Add String() implementations for some structs (#20)

drone/commit.go

@@ -55,6 +55,10 @@ type (
 	}
 )
 
+func (c Commit) String() string {
+	return c.SHA
+}
+
 func (a Author) String() string {
 	return a.Username
 }

drone/repo.go

@@ -37,3 +37,7 @@ type Repo struct {
 	// Private to show if the repo is private.
 	Private bool
 }
+
+func (r Repo) String() string {
+	return r.Slug
+}

drone/semver.go

@@ -37,3 +37,7 @@ type SemVer struct {
 	// Error is the semantic version parsing error if the tag was invalid.
 	Error string
 }
+
+func (s SemVer) String() string {
+	return s.Version
+}

drone/stage.go

@@ -5,9 +5,7 @@
 
 package drone
 
-import (
-	"time"
-)
+import "time"
 
 // Stage represents a build stage.
 type Stage struct {
@@ -62,3 +60,7 @@ type Stage struct {
 	// DependsOn is a list of dependencies for the current build stage.
 	DependsOn []string
 }
+
+func (s Stage) String() string {
+	return s.Name
+}

drone/step.go

@@ -13,3 +13,7 @@ type Step struct {
 	// Number is the numeric value of the step.
 	Number int
 }
+
+func (s Step) String() string {
+	return s.Name
+}

drone/system.go

@@ -16,3 +16,7 @@ type System struct {
 	// Version for the system version.
 	Version string
 }
+
+func (s System) String() string {
+	return s.Host
+}