bug(5015) pg doesnt support create table if not exists for 9.0 and below

lib/dialects/postgres/query-generator.js

@@ -5,7 +5,8 @@ var Utils = require('../../utils')
   , util = require('util')
   , DataTypes = require('../../data-types')
   , AbstractQueryGenerator = require('../abstract/query-generator')
-  , primaryKeys = {};
+  , primaryKeys = {}
+  , semver = require('semver');
 
 var QueryGenerator = {
   options: {},
@@ -42,7 +43,11 @@ var QueryGenerator = {
 
     primaryKeys[tableName] = [];
 
-    var query = 'CREATE TABLE IF NOT EXISTS <%= table %> (<%= attributes%>)<%= comments %>'
+    var databaseVersion = Utils._.get(self, 'sequelize.options.databaseVersion', 0);
+    //Postgres 9.0 does not support CREATE TABLE IF NOT EXISTS, 9.1 and above do
+    var query = 'CREATE TABLE ' +
+                ( (databaseVersion === 0 || semver.gte(databaseVersion, '9.1.0')) ? 'IF NOT EXISTS ' : '') +
+                '<%= table %> (<%= attributes%>)<%= comments %>'
       , comments = ''
       , attrStr = []
       , i;

test/unit/sql/create-table.test.js

@@ -29,4 +29,3 @@ describe(Support.getTestDialectTeaser('SQL'), function() {
     });
   });
 });
-