Replace the doors mod

mods/doors/README.txt

mods/doors/init.lua

mods/doors/textures/door_brown.png

mods/doors/textures/door_grey.png

mods/doors/textures/door_steel.png

mods/doors/textures/door_steel_a.png

mods/doors/textures/door_steel_b.png

mods/doors/textures/door_wood_a_r.png

mods/doors/textures/door_wood_b_r.png