Add database setup information

Author: janisozaur

readme.md

@@ -14,6 +14,25 @@ docker pull mcr.microsoft.com/dotnet/sdk:10.0
 docker run -v "$(pwd)":/work -w /work -it -p 5000:80 mcr.microsoft.com/dotnet/sdk:10.0 bash
 ```
 
+## Database
+```
+# in terminal:
+docker volume create rethinkdb_data
+docker run --rm -it --name rethinkdb-manual -v rethinkdb_data:/data -p 8080:8080 -p 28015:28015 -p 29015:29015 rethinkdb
+
+# in browser:
+http://localhost:8080
+
+# go to Data Explorer and run:
+r.dbCreate("live")
+
+r.db("rethinkdb").table("users").insert({id: "openrct2-api-live", password: "<PASSWORD>"}, { conflict: "replace" })
+
+r.grant("openrct2-api-live", {"config": true})
+
+# remember to replace <PASSWORD> with a strong password and update api.config.yml accordingly
+```
+
 ## Building / Launching
 ```
 cd src/OpenRCT2.API