Fix typo of DB migration script

Signed-off-by: Takeaki Matsumoto <takeaki.matsumoto@ntt.com>

Author: takmatsu

lib/migrations/20171009121200-longtext-for-mysql.js

@@ -4,13 +4,13 @@ module.exports = {
     queryInterface.changeColumn('Notes', 'content', {type: Sequelize.TEXT('long')})
     queryInterface.changeColumn('Revisions', 'patch', {type: Sequelize.TEXT('long')})
     queryInterface.changeColumn('Revisions', 'content', {type: Sequelize.TEXT('long')})
-    queryInterface.changeColumn('Revisions', 'latContent', {type: Sequelize.TEXT('long')})
+    queryInterface.changeColumn('Revisions', 'lastContent', {type: Sequelize.TEXT('long')})
   },
 
   down: function (queryInterface, Sequelize) {
     queryInterface.changeColumn('Notes', 'content', {type: Sequelize.TEXT})
     queryInterface.changeColumn('Revisions', 'patch', {type: Sequelize.TEXT})
     queryInterface.changeColumn('Revisions', 'content', {type: Sequelize.TEXT})
-    queryInterface.changeColumn('Revisions', 'latContent', {type: Sequelize.TEXT})
+    queryInterface.changeColumn('Revisions', 'lastContent', {type: Sequelize.TEXT})
   }
 }