Update README.md

Author: arduino12

README.md

@@ -5,6 +5,7 @@ A simple library to interface with RDM6300 RFID reader.
 * Fast and single tag reading, even if it held near the antenna for a while.
 * Using a single configurable GPIO pin.
 * Can tell if the tag is still near the antenna.
+* Both hardware and software uart (serial) support on esp8266.
 
 ## Getting Started
 
@@ -14,7 +15,7 @@ A simple library to interface with RDM6300 RFID reader.
 * Microcontroller (arduino, esp8266, esp32...).
 * Jump-Wires (Resistors of 1K and 2K if you are using 3.3V based microcontroller).
 
-![alt text](https://lh3.googleusercontent.com/xaZxf4aRQCM8teJDho_jtRJmqZsE5Da2rX5pBThctffH6az2lyWtEnTPPcqcCPayg55p8bbobJLVRCW-M5e5ywGp2nlcUq1dZAzxXvzCjm2zXq0e8K1EeNI6WG2G_gApMI90Lkt_rYKPiamGgXwFvjGCE-rI2NmOciinfDIbdIpCHMlPf-0WRTxo7s7hSY86b0BDnNRpCKgZBeJizIM3karj6Y5EwH3xP5heDDr2sunw4YWF5EQCmVrU-ipS8Umzp5EnyQELH0nW9JfAXFHkN4aCVoO2QW2oOMRajGpEW8IGxAQUEmLHmYQEsqV1dUd4aVvkTFnN-H2JoOssspcIpXoHExpLLxOwlk2QjT6KVw7hQaeENwv-my6gEbTOzfg9DoC__j6WMkjewsaph408ALDsqxjm5lOoZDl9ag8nwqXi0SmmCphq7FiwG9pbyrTCbOqh4V8Dep4vXg3lkchZeedWLSU51xIJjN3K2RYG9tSiemIO4TjjNB_fEZiq5dbakNeSjKdyjjCUoKsWTOsrDlkBSpvC7U_2VcrU_4eExXkf8qyY_HPYD-X6QRodMqBzvQJUOlC_UIihDbZd8MUW0WMsGBCKAzVScL4msemZphtI4vhWAwNj4l1ss5P9hCkAdhpWPJkzz8hIYvBt3HLfxPv9NL0S12C1TKVNEGmu_PZkPvrk4j1I0hXwVA=w688-h578-no "rdm6300_connections")
+![rdm6300_connections](../master/doc/rdm6300_connections.png "rdm6300_connections")
 
 ### Software
 A simple RFID to serial reciver example can be found at: