add 'git credential' plumbing command
The credential API is in C, and not available to scripting languages.
Expose the functionalities of the API by wrapping them into a new
plumbing command "git credentials".
In other words, replace the internal "test-credential" by an official Git
command.
Most documentation writen by: Jeff King <peff@peff.net>
Signed-off-by: Pavel Volek <Pavel.Volek@ensimag.imag.fr>
Signed-off-by: Kim Thuat Nguyen <Kim-Thuat.Nguyen@ensimag.imag.fr>
Signed-off-by: Javier Roucher Iglesias <Javier.Roucher-Iglesias@ensimag.imag.fr>
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>