from datetime import datetime
import matplotlib.pyplot as plt

dates = [datetime.strptime(date.strip(), "%Y-%m-%dT%H:%M:%S")
         for date in open("commits.txt")]

dates = dates[:148]
dates, commits = zip(*[(date, i) for (i, date) in enumerate(sorted(dates))])
fig = plt.figure()
plt.plot(dates, commits)
plt.grid()
plt.ylabel("Cumulative commits")
fig.autofmt_xdate()
plt.savefig("commits.pdf")