Multiple record with common field names

[sapristi]

Hello,

It seems when running decco over multiple record type with common keys, for example:

[@decco]
type record1 = {field1: int};

[@decco]
type record2 = {
  field1: int,
  field2: string,
};

then a warning is raised:

Warning number 41 (configured as error) 
  (No file name)
  
  field1 belongs to several types: record2 record1
The first one was selected. Please disambiguate if this is wrong.

I finally found out the warning can be specified as not-an-error in bsconfig.json, but it might be good to have a few lines about this in the README.