update readme

backend/README.md

@@ -22,20 +22,27 @@ pip freeze > requirements.txt
 ```
 
 ## db cheat:
+After db schema change:
 ```
-flask db migrate -m "users table"
+flask db migrate -m "add users table"
 flask db upgrade
+```
 
-flask db downgrade [base]
+Dump data if db in good state:
+```
+flask db downgrade base
 flask db upgrade
+```
 
-full reset?
+Full reset:
+```
 rm app.db
 rm -r migrations
 flask db init
 flask db migrate
 flask db upgrade
 ```
+
 ## build notes:
 
 Dockerfile needs dockerignore or preferably explicitly defined copies for: