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Actually the previous line was semantically correct but syntactically wrong (it was written as 'tweet.save' instead of 'tweet.save()')

My BaseModel which is the base class of my Tweet class didn't extend from ActiveAndroid.Model, so that's why all AA methods like save() etc. were giving me compile time error.

The Tweet class here extends from Model, so it should work.
Merge pull request #4 from kapoor/patch-2

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