fix(template): fix unnoticed error introduced in the last merge request

Wrong migrations have been generated

Author: wzrdtales

lib/migration.js

@@ -122,7 +122,7 @@ Migration.prototype.sqlFileLoaderTemplate = function() {
     '};',
     '',
     'exports.up = function(db) {',
-    '  var filePath = path.join(__dirname, \'sqls', this.name.replace(
+    '  var filePath = path.join(__dirname, \'sqls\', \'' + this.name.replace(
       '.js', '') + '-up.sql\');',
     '  return new Promise( function( resolve, reject ) {',
     '    fs.readFile(filePath, {encoding: \'utf-8\'}, function(err,data){',
@@ -138,7 +138,7 @@ Migration.prototype.sqlFileLoaderTemplate = function() {
     '};',
     '',
     'exports.down = function(db) {',
-    '  var filePath = path.join(__dirname, \'sqls', this.name.replace(
+    '  var filePath = path.join(__dirname, \'sqls\', \'' + this.name.replace(
       '.js', '') + '-down.sql\');',
     '  return new Promise( function( resolve, reject ) {',
     '    fs.readFile(filePath, {encoding: \'utf-8\'}, function(err,data){',