Update README with environment variable placeholders

Added placeholders for environment variables in README.

Author: PaoloGiacosa

README.md

@@ -1,9 +1,10 @@
 This is the part of Outdoorz which implement the business logic of the social network 
 
 All you have to do is create a .env file which has to be the same in OutdoorzSocial and OutdoorzMedia with the following fields:
-DB_PASSWORD=<db password>
-ENCRYPTION_KEY=<encryption key>
-JWT_SECRET=<jwt secret>
+
+DB_PASSWORD= 
+ENCRYPTION_KEY=
+JWT_SECRET=
 
 Note: DB_PASSWORD must be the same ad in the .env in the same dir as docker-compose or service.yaml
 The jwt secret must be long at least 32 character.