Support multiple service tags for identifying the db

main.go

@@ -24,7 +24,7 @@ func main() {
 	log.Infof("genesis-index starting up")
 
 	var d *db.DB
-	if dsn, err := ParseVcap(os.Getenv("VCAP_SERVICES"), "postgres", "uri"); err == nil {
+	if dsn, err := ParseVcap(os.Getenv("VCAP_SERVICES"), []string{"postgres", "postgresql"}, "uri"); err == nil {
 		d, err = Database("postgres", fmt.Sprintf("%s?sslmode=disable", dsn))
 		if err != nil {
 			log.Infof("Unable to connect to database: %s", err)

vcap.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 )
 
-func ParseVcap(src, tag, subkey string) (string, error) {
+func ParseVcap(src string, tags []string, subkey string) (string, error) {
 
 	var services map[string][]struct {
 		Credentials    map[string]interface{} `json:"credentials"`
@@ -25,10 +25,13 @@ func ParseVcap(src, tag, subkey string) (string, error) {
 	for _, l := range services {
 		for _, service := range l {
 			tagged := false
+		TAGS:
 			for _, actual := range service.Tags {
-				if tag == actual {
-					tagged = true
-					break
+				for _, tag := range tags {
+					if tag == actual {
+						tagged = true
+						break TAGS
+					}
 				}
 			}