fix: migration syntax and insert query

[zinderic]

I noticed that the example was not working because the migration could not run:

sqlite> CREATE TABLE IF NOT EXISTS google_tokens (
(x1...>   id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
(x1...>   user_id INTEGER NOT NULL UNIQUE,
(x1...>   access_secret TEXT NOT NULL,
(x1...>   refresh_secret TEXT NOT NULL,
(x1...>   created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
(x1...>   FOREIGN KEY (user_id) REFERENCES users(id) CONFLICT REPLACE
(x1...> );
Parse error: near "CONFLICT": syntax error
  AMP,   FOREIGN KEY (user_id) REFERENCES users(id) CONFLICT REPLACE );
                                      error here ---^
sqlite> 

Moving that conflict resolution to the insert query seems to work fine.