Update README.md

Author: me-no-dev

README.md

@@ -1 +1,21 @@
-#Arduino framework for ESP32
+Arduino core for ESP32 WiFi chip
+===========================================
+
+### Installation
+- Install Arduino 1.6.9
+- Go to Arduino directory
+- Clone this repository into hardware/espressif/esp32 directory (or clone it elsewhere and create a symlink)
+```bash
+cd hardware
+mkdir espressif
+cd espressif
+git clone https://github.com/espressif/arduino-esp32.git esp32
+```
+- Download binary tools (you need Python 2.7)
+```bash
+cd esp32/tools
+python get.py
+```
+- Restart Arduino
+
+![Pin Functions](doc/esp32_pinmap.png)