fix(postgres/query-generator): syntax error with auto-increment SMALLINT (#9406)

lib/dialects/postgres/query-generator.js

@@ -843,6 +843,9 @@ const QueryGenerator = {
       if (_.includes(dataType, 'BIGINT')) {
         dataType = dataType.replace(/SERIAL/, 'BIGSERIAL');
         dataType = dataType.replace(/BIGINT/, '');
+      } else if (_.includes(dataType, 'SMALLINT')) {
+        dataType = dataType.replace(/SERIAL/, 'SMALLSERIAL');
+        dataType = dataType.replace(/SMALLINT/, '');        
       } else {
         dataType = dataType.replace(/INTEGER/, '');
       }

test/unit/dialects/postgres/query-generator.test.js

@@ -137,8 +137,12 @@ if (dialect.match(/^postgres/)) {
 
       createTableQuery: [
         {
-          arguments: ['myTable', {int: 'INTEGER', bigint: 'BIGINT'}],
-          expectation: 'CREATE TABLE IF NOT EXISTS \"myTable\" (\"int\" INTEGER, \"bigint\" BIGINT);'
+          arguments: ['myTable', {int: 'INTEGER', bigint: 'BIGINT', smallint: 'SMALLINT' }],
+          expectation: 'CREATE TABLE IF NOT EXISTS \"myTable\" (\"int\" INTEGER, \"bigint\" BIGINT, \"smallint\" SMALLINT);'
+        },
+        {
+          arguments: ['myTable', {serial: 'INTEGER SERIAL', bigserial: 'BIGINT SERIAL', smallserial: 'SMALLINT SERIAL' }],
+          expectation: 'CREATE TABLE IF NOT EXISTS \"myTable\" (\"serial\"  SERIAL, \"bigserial\"  BIGSERIAL, \"smallserial\"  SMALLSERIAL);'
         },
         {
           arguments: ['myTable', {title: 'VARCHAR(255)', name: 'VARCHAR(255)'}],