Add calendar integration

name: 🚀 Calendar Integration about: As a gym goer, I should be able to integrate my workout schedule to my calendar.

Pull Request

Related Issue As a gym goer, I should be able to integrate my workout schedule to my calendar.

Describe the solution you implemented Integrate the events from the device default calendar into the application

Describe alternatives you've considered This is the only solution.

How Has This Been Tested? Manually.

Screenshots Calendar 59813686_2252064648165884_6447488730184810496_n Events 59758120_426356521273343_5732474450331303936_n

[ ] Bug fix (non-breaking change which fixes an issue)
[x] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to change)
[x] I have read the CONTRIBUTING document.
[x] My code follows the code style of this project.
[ ] My change requires a change to the documentation.
[ ] I have updated the documentation accordingly.
[ ] I have added tests to cover my changes.
[ ] All new and existing tests passed.