added config at the correct location

keyboards/boardsource/unicorne/readme.md

@@ -0,0 +1,25 @@
+# Unicorne
+
+![image](https://i.imgur.com/akJJFUmh.jpeg)
+
+* Keyboard Maintainer: [waffle87](https://github.com/waffle87)
+* Hardware Supported: Unicorne PCBs w/ integrated RP2040 microcontroller
+* Hardware Availability: [boardsource.xyz](https://boardsource.xyz)
+
+Make example for this keyboard (after setting up your build environment):
+
+    make boardsource/unicorne:default
+
+Flashing example for this keyboard:
+
+    make boardsource/unicorne:default:flash
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
+
+## Bootloader
+
+Enter the bootloader in 3 ways:
+
+* **Bootmagic reset**: Hold down the key at (0,0) in the matrix (the top left key) and plug in the keyboard
+* **Physical reset button**: Briefly press the button on the back of the PCB
+* **Keycode in layout**: Press the key mapped to `QK_BOOT` if it is available