Scenario
The iBanker boss in Hong Kong requests you to create a Facebook-like application within a week. The application should have iOS...
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Rails with devise for user management.
SendGrid or similar for handling outgoing email.
The iOS and Android apps would just be a web view.
If I'm getting HK$5000 and they're getting HK$3,000,000, I'll let them worry about making it scale. ;)
I wouldn't. There's no reason (today) that a facebook like service needs a dedicated native app for android and ios. A website will suffice.