You can check your past contributions in Github.
Github now allows you to view your day wise contribution throughout the year.
You can also view your contributions within a selected time span too.
First you need to login to Github.com.
Click on Contributions.
There you will find a calendar view.
Click on any date you like to see and your Contribution Activity will be displayed.
Now if you like to see your contributions within a selected time span then select the starting day and hold down the Shift key and select the end day.
Now your contribution between those two days will be displayed.
You can also read: How to add Repository in Github .