Update README.md

README.md

@@ -14,6 +14,13 @@ PS. I'm not a native English speaker. I'll be grateful if you participate in cor
 1. The main prerequisite is availability of your own [nightscout site](https://github.com/nightscout/cgm-remote-monitor).
 2. Blood sugar level data from your CGM must be sent to Nightscout site (for instance through [xDrip+](https://github.com/NightscoutFoundation/xDrip))
 
+### Nightscout site permission
+⚠️ It is nessesary to create user with reed permission! ⚠️ 
+1. Log in to the admin panel of your Nightscout site (e.g. https://some-cgm.site.com/admin/)
+2. Create a new role using the pattern ***:*:read**
+3. Create a new subject using role created in step 2
+4. Use generated access token of the role in application window "Source settings"
+
 ## Installation
 1. Download [installer](https://github.com/SergeyRock/nightscout-watcher/releases) (only win32 version is available)
 2. Install and start executable