manual described updating variables.env file but was not read by frontend unless forced

[beijkm]

actions taken:

-followed step 6 from README.md
-verified that variables.env contain correct api tokens
-frontend kept using default variables from first start
-needed to manually unlink first on /settings (not listed as required action in README.md) as it kept saying preview token was invalid

can be reproduced by temporarily moving variables.env > variables.tmp

• frontend will persistently use variables set in frontend from previous session.

developer experience can be improved by displaying on the server (e.g. npm run start:dev) which variables it is using making the connection to the contentful servers. Additionally a Step 8 "verify on /settings that your credentials are being used"