Making ubuntu as default OS on windows 10

I was able to successfully  install ubuntu  by following the documentation
from ubuntu website but my computer was not  booting  ubuntu by default .

After struggling a lot, Step 3 worked for me . You can directly go to step 3 instead of trying Step 1 and 2

1)  I executed the below instructions which I found after searching in google

sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

The above steps installed boot-repair and executed the 

boot-repair utility. 

2) The above step did not help me and my computer was still booting to 

Windows 10 by default. 

Then I did the below step after rebooting to windows 10. 

Ran the command prompt as administrator and executed the below step
 

bcdedit /set {bootmgr} path \EFI\ubuntu\shimx64.efi

Basically the above step made the GRUB as default bootloader 

instead of Windows Boot Manager which is also referred as 

OS boot Manager in the BIOS.

This step was advised in the step 1 by boot-repair utility itself 

if the boot-repair does not work.

3) The above solution only worked for one time and again the computer 

started to boot windows 10 by default.

Then I tried the below solution which finally worked for me

Invoke terminal

Sudo su 

cd  /boot/efi/EFI

mv Boot Boot_bak

cp -Rf ubuntu Boot

cd Boot

mv  shimx64.efi bootx64.efi 

cd ../

mv Microsoft Microsoft_bak