Add bar chart showing commits per day to profile

Use nvd3 to show a bar chart showing commits per day over the past 90
days on the profile page.

Change-Id: I888b40f59a7eff6270e61ea1b2699f9dcf5adf5f
Reviewed-on: https://gerrit.causes.com/22013
Reviewed-by: Jimmy Kittiyachavalit <jimmy@causes.com>
Tested-by: Jimmy Kittiyachavalit <jimmy@causes.com>