Clarify readme

[eljoth]

I faced the issue to not be able to import an existing config with the error, that I am trying to import a file into the wrong collection. Via File selection it told me to override the file, pasting the path resulted in previous mentioned behaviour.

I needed to initially load the file to create the project via the native insomnia functionality. Finally I could set up the sync with the configuration file.

I documented this workflow in the README.md so it will be easier for successors to set things up :).

[NickRimmer]

Great, thank you. I was looking to a few ways, how to create a collection for the first time in a more friendly way. Because of insomnia initially doesn't support import from other collections, I was able to do this only with collections db work directly. But inserting of anything directly to db will not be stable solution, as insomnia authors can change it in any moment.

Anyway, thank you for your changes (;