iOS - sqlite database replacement make replaced db readonly

While working in an iOS app, i have created a database when app launches. I also had a preloaded database in app/resource which actually same database with some preloaded data. When i replaced app database with preloaded app/resource database with NSFileManager copy API,

[fileManager copyItemAtURL:testDbUrl toURL:destination error:&error];

Problem

I found newly replaced database became readonly. I cannot execute any insert operation but reading is fine. How can i make newly replaced database writable.