Allow PUT method: UPSERT of a single row

test/fixtures/data.sql

@@ -343,3 +343,6 @@ INSERT INTO employees VALUES
 
 TRUNCATE TABLE tiobe_pls CASCADE;
 INSERT INTO tiobe_pls VALUES ('Java', 1), ('C', 2), ('Python', 4);
+
+TRUNCATE TABLE only_pk CASCADE;
+INSERT INTO only_pk VALUES (1), (2);

test/fixtures/privileges.sql

@@ -65,6 +65,7 @@ GRANT ALL ON TABLE
     , perf_articles
     , employees
     , tiobe_pls
+    , only_pk
 TO postgrest_test_anonymous;
 
 GRANT INSERT ON TABLE insertonly TO postgrest_test_anonymous;

test/fixtures/schema.sql

@@ -631,6 +631,9 @@ CREATE TABLE no_pk (
     b character varying
 );
 
+CREATE TABLE only_pk (
+    id integer primary key
+);
 
 --
 -- Name: nullable_integer; Type: TABLE; Schema: test; Owner: -