fix: allow inserting files without requiring select permissions

[dbarrosop]

Solves #69

[elitan]

Does this mutation work?

I would expect it to be:

mutation InitializeFile($id: uuid) {insertFiles(objects: [{id: $id}]) {affected_rows}}

Note the [] after objects:.

[elitan]

@dbarrosop I guess the [] was not needed?

[dbarrosop]

sorry, I thought I had answered and I forgot to press comment.

You don't need the [], otherwise tests would have blown up :P As a matter of fact, that specific query was built by hasura's explorer (by default they don't add the [], you have to do it "manually" in the editor).