App should Upgrade Gradle Version to 2.2.3

[nitish1211]

The current gradle version used in this project is 1.2.3 which is extremely old.
This doesn't allow for a proper build in the newer versions of Android studio(ver 2.2.3).

Advantages of using newer Gradle version:

• Instant Run- Makes it faster for the developers to build and test code.

• Faster Build

Fix : I suggest upgrading it to 2.2.3 or 2.3

@sandarumk @top-gun007 Your thoughts on this?

[codingblazer]

@sandarumk This will be fixed in #409