Postgres 'INSERT' fix and association hasOne fix for PK other than 'id'

Hi,
I am using postgres DB and found that insert doesn't return correct key value if PK has name other than 'id', same goes for associations hasOne. I haven't looked at hasMany but i guess it will be same small fixture as in hasOne. Of course ignore package.json file.

Best regards
Łukasz Chelmicki

PS.
Please let me know when you merge my code.