Add README and start to work on build for prod guide

docs/SETUP_PROD.md

@@ -0,0 +1,48 @@
+# Configure project for production
+
+## Create production build
+
+### Central
+The production release of central backend and frontend can be realised on a computer which has NodeJS and Rust installed by executing the following command at the root of the project:
+
+```bash
+make
+```
+
+The backend will be available at this location:
+
+```
+central_backend/target/release/central_backend
+```
+
+### Python device
+The Python device isn't production ready yet.
+
+
+### ESP32 device
+
+#### Flashing the device directly
+Use the following commands to flash a device (inside ESP-IDF environnment):
+
+```bash
+idf.py build
+idf.py flash
+```
+
+
+#### Getting an OTA update
+Use the following command to build an OTA update:
+
+```bash
+idf.py build
+```
+
+The OTA update is then located in `build/main.bin`
+
+
+## Pre-requisites
+* A server running a recent Linux (Debian / Ubuntu preferred) with `central` as hostname
+* DHCP configured on the network
+
+## Configure server
+TODO