How to upgrade database version in sqlite and add new column in table in swift

I've already created sqlite tables for my app, but now I want to add a new column in table to the database. ALTER TABLE will help me in this problem but first i want to check the database version. i am using PRAGMA user_version to check the user version and update the user_version but it always returning user_version as 0.

var database: FMDatabase? = nil

    class func getInstance() -> ModelManager{
        if(sharedInstance.database == nil){
            sharedInstance.database = FMDatabase(path: Util.getPath("XXXX.sqlite"))
        }
        return sharedInstance
    }


    func userVersion(){
        sharedInstance.database!.open()
        var userVer = Int()
        let resultSet = sharedInstance.database?.executeQuery("pragma user_version", withArgumentsInArray: nil)
        userVer =  Int(resultSet!.intForColumn("user_version"))
        print("user version : ",userVer)
        sharedInstance.database!.close()
    }

    func updateUserVersion(){
        sharedInstance.database!.open()
        sharedInstance.database?.executeUpdate("PRAGMA user_version=1", withArgumentsInArray: nil)
        sharedInstance.database!.close()
    }