README: Include Difference in Connection Strings depending on Cloud SQL Generation

Fixes #481, #484

Author: lennrt

AUTHORS

@@ -31,6 +31,7 @@ Julien Lefevre <julien.lefevr at gmail.com>
 Julien Schmidt <go-sql-driver at julienschmidt.com>
 Kamil Dziedzic <kamil at klecza.pl>
 Kevin Malachowski <kevin at chowski.com>
+Lennart Rudolph <lrudolph at hmc.edu>
 Leonardo YongUk Kim <dalinaum at gmail.com>
 Luca Looz <luca.looz92 at gmail.com>
 Lucas Liu <extrafliu at gmail.com>

README.md

@@ -337,11 +337,16 @@ TCP on a remote host, e.g. Amazon RDS:
 id:password@tcp(your-amazonaws-uri.com:3306)/dbname
 ```
 
-Google Cloud SQL on App Engine:
+Google Cloud SQL on App Engine (First Generation MySQL Server):
 ```
 user@cloudsql(project-id:instance-name)/dbname
 ```
 
+Google Cloud SQL on App Engine (Second Generation MySQL Server):
+```
+user@cloudsql(project-id:regionname:instance-name)/dbname
+```
+
 TCP using default port (3306) on localhost:
 ```
 user:password@tcp/dbname?charset=utf8mb4,utf8&sys_var=esc%40ped