Update README.md with project description and architecture diagram

README.md

@@ -1,2 +1,49 @@
-# private_health
+# Private Health
 
+This project aims to create the necessary building blocks in order to allow collect and analyze one's personal health data in a privacy-oriented manner. Instead of closed-source apps and dubious clouds, it should use a FLOSS stack.
+
+
+## Architecture
+
+```mermaid
+flowchart LR
+  scale(("bathroom<br>scale"))
+  A["openscale"]
+  B["openscale sync"]
+  hc["HealthConnect API<br>(or similar)"]
+
+  fitness_tracker(("fitness<br>tracker"))
+  gb["Gadgetbridge"]
+  gb_sync["(Gadgetbridge sync?)"]
+
+  nc[("Nextcloud")]
+
+  bpm(("blood<br>pressure<br> monitor"))
+  --> bpm_app["BPM app"]
+  --> hc
+
+  scale-->A
+  --> B
+  --> hc
+  
+  fitness_tracker
+  --> gb
+  --> gb_sync
+  --> hc
+
+  hc --> nha["Nextcloud (health) app"]
+
+  nha --> nc
+
+  nc --> cA["Web UI<br>(Dashboard, statistics)"]
+  nc --> cB["mobile devices"]
+  nc --> cC["...other clients..."]
+
+  classDef green fill:#8fb935,stroke:#333;
+  classDef yellow fill:#e6e22e,stroke:#333;
+  classDef orange fill:#e09c3b,stroke:#333,stroke-width:4px;
+  classDef red fill:#e64747,stroke:#333,stroke-width:4px;
+  class A,B,gb,hc green;
+  class bpm_app,gb_sync,cA,nc orange;
+  class nha red;
+```