Added API documentation for Land Transport Authority DataMall, Singapore

README.md

@@ -1495,6 +1495,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Icelandic APIs](http://docs.apis.is/) | Open APIs that deliver services in or regarding Iceland | No | Yes | Unknown |
 | [Impala Hotel Bookings](https://docs.impala.travel/docs/booking-api/) | Hotel content, rates and room bookings | `apiKey` | Yes | No |
 | [Izi](http://api-docs.izi.travel/) | Audio guide for travellers | `apiKey` | Yes | Unknown |
+| [Land Transport Authority DataMall, Singapore](https://datamall.lta.gov.sg/content/dam/datamall/datasets/LTA_DataMall_API_User_Guide.pdf) | Singapore transport information | `apiKey` | No | Unknown |
 | [Metro Lisboa](http://app.metrolisboa.pt/status/getLinhas.php) | Delays in subway lines | No | No | No |
 | [Navitia](https://doc.navitia.io/) | The open API for building cool stuff with transport data | `apiKey` | Yes | Unknown |
 | [Open Charge Map](https://openchargemap.org/site/develop/api) | Global public registry of electric vehicle charging locations | `apiKey` | Yes | Yes |