docs: add emulator page

README.md

@@ -15,6 +15,7 @@ It runs both inside of the device and also in the TREZOR Emulator.
 
 * [API](docs/api.md)
 * [Build instructions](docs/build.md)
+* [Emulator](docs/emulator.md)
 * [Testing](docs/testing.md)
 * [Bootloader](docs/bootloader.md)
 * [Hardware](docs/hardware.md)

docs/emulator.md

@@ -0,0 +1,7 @@
+# Emulator
+
+![emulator](emulator.jpg)
+
+1. [build](docs/build.md) the emulator
+2. run `emu.sh`
+3. to use [bridge](https://github.com/trezor/trezord-go) with the emulator support, start it with `trezord -e 21324`