In your sdk_config.h file, find the following lines and set them as follows:
#define TWI_ENABLED 1
#define TWI0_ENABLED 1Most of this driver is copied straight from ST, with the exception of platform/src/vl53l0x_i2c_platform.c, which implements the i2c driver on the nrf51, and contains the pin definitions for the i2c bus. Change those pin definitions to match your board layout.
main.c is an example of how to use the driver, but is not tested and may not compile as written. Please submit a pull request with any necessary changes to make it work out of the box.