Step 1. Generate an SSH key
cd ~/.ssh &&
ssh-keygen -t rsa -f ~/.ssh/mage2.pro -C "the key name"
Do not set a passphrase for it.
Step 2. Assign the SSH key to the code.dmitry-fedyuk.com domain
Do it in the ~/.ssh/config file (create it if absent):
Host code.dmitry-fedyuk.com
IdentityFile ~/.ssh/mage2.pro
http://dbushell.com/2013/01/27/multiple-accounts-and-ssh-keys/
Step 3
If you have create a new ~/.ssh/config file on the previous step, then you should set the proper filesystem permissions for it:
chmod 600 ~/.ssh/config
Otherwise, you will get the «Bad owner or permissions on ~/.ssh/config» failure on the composer require step (step 8 of the installation process).
Step 4. Register this SSH key in the code.dmitry-fedyuk.com repository
Copy the contents of the mage2.pro.pub file and paste it to your account in the code.dmitry-fedyuk.com repository.