Arduino Real Time Clock library.
An RTC library with deep device support.
Now supports esp8266. Now supports SoftwareWire library. Now supports AT24C32 EEPROM which is often included on on DS3231 boards
For bugs, make sure there isn't an active issue and then create one.
Installing This Library (prefered, you just want to use it)
Open the Library Manager and search for "Rtc by Makuna" and install
Installing This Library From GitHub (advanced, you want to contribute)
Create a directory in your Arduino\Library folder named "Rtc"
Clone (Git) this project into that folder.
It should now show up in the import list when you restart Arduino IDE.