Better error message when we cant connect to the database #49
Description
For now, when we cannot connect to the database whether it is from a wrong configuration or the database being down, we get this very unhelpful error message: Database error: CONNECTION UNAVAILABLE.
It would be better to have indications on what to do next like checking the configuration, the environment variables or the state of the database.
A reminder of the connection data could be great if possible.
An example of an error message could be:
Impossible to connect to database my_db at address localhost:5432 with user toto ! Check that your configuration is correct and that the database is available.