message: Clarifying user rights.
diff: +# Pigallery2 user rights
  +
  +The following users are supported in the app with these rights:
  | id | Role | rights | who has it |
  -|----|---------------|----------------------|------------|
  +|----|---------------|-----------------------------------------|------------|
  | 1 | Limited Guest | listing directory | using shared link |
  | 2 | Guest | + search | no one (you can set manually in the db, if necessary) |
  -| 3 | User | + share | default role |
  -| 4 | Admin | + settings | default (pregenerated) user (also the default right if authentication is off) |
  +| 3 | User | + share, list faces, create random link | default role |
  +| 4 | Admin | + settings, see duplicate photos | default (pregenerated) user (also the default right if authentication is off) |
  | 5 | Developer | + see errors | no one (you can set manually in the db, if necessary) |
  +
  +**Note:** If you would like to set a user rights and does not work with the role name (string) use its id.
  