Data race during query factory initialisation

[o1egl]

Describe the bug
In my application I initialize goqu.Database during startup and provide it as dependency to my services. During running my integration tests I got data race in queryFactory() function. You can reproduce it by running the code below with turned on races detector.

To Reproduce

dbConn, err := sql.Open("postgres", connStr)
db := goqu.New("postgres", dbConn)
for i=0; i < 2; i++ {
    go func(){
        db.From("foo").ScanStruct(...)
        ...
    }()
}

Dialect:

• postgres
• mysql
• sqlite3