Add VersionString func to print out full app version

pkg/command/version.go

@@ -1,5 +1,10 @@
 package command
 
+import (
+	"fmt"
+	"strings"
+)
+
 const (
 	// Version is the current Pgweb application version
 	Version = "0.11.12"
@@ -32,3 +37,19 @@ func init() {
 	Info.BuildTime = BuildTime
 	Info.GoVersion = GoVersion
 }
+
+func VersionString() string {
+	chunks := []string{fmt.Sprintf("Pgweb v%s", Version)}
+
+	if GitCommit != "" {
+		chunks = append(chunks, fmt.Sprintf("(git: %s)", GitCommit))
+	}
+	if GoVersion != "" {
+		chunks = append(chunks, fmt.Sprintf("(go: %s)", GoVersion))
+	}
+	if BuildTime != "" {
+		chunks = append(chunks, fmt.Sprintf("(build time: %s)", BuildTime))
+	}
+
+	return strings.Join(chunks, " ")
+}