Add 'PGRST' error code to differentiate from PostgreSQL errors

test/spec/Feature/Query/UpdateSpec.hs

@@ -33,7 +33,7 @@ spec = do
       it "fails with 400 and error" $
         request methodPatch "/simple_pk" [] "}{ x = 2"
           `shouldRespondWith`
-          [json|{"message":"Error in $: Failed reading: not a valid json value at '}{x=2'"}|]
+          [json|{"message":"Error in $: Failed reading: not a valid json value at '}{x=2'","code":"PGRST102","details":null,"hint":null}|]
           { matchStatus  = 400,
             matchHeaders = [matchContentTypeJson]
           }
@@ -42,7 +42,7 @@ spec = do
       it "fails with 400 and error" $
         request methodPatch "/items" [] ""
           `shouldRespondWith`
-          [json|{"message":"Error in $: not enough input"}|]
+          [json|{"message":"Error in $: not enough input","code":"PGRST102","details":null,"hint":null}|]
           { matchStatus  = 400,
             matchHeaders = [matchContentTypeJson]
           }