Improve v0.1.1 documentation - add notice about public key

documentation/v0.1.1/getting-started.md

@@ -227,6 +227,37 @@ If your GitHub repository is **private** you have to configure SSH or username/p
 
 ### SSH authentication
 
+#### Generate SSH Keys
+
+There are two methods of SSH private key generation:
+
+```bash
+$ openssl genrsa -out <filename> 2048
+```
+
+or
+
+```bash
+$ ssh-keygen -t rsa -b 2048
+$ ssh-keygen -p -f <filename> -m pem
+```
+
+Then copy content from generated file. 
+
+#### Public key
+
+If you want to upload your public key to your Git server you need to extract it.
+
+If key was generated by `openssl` then you need to type this to extract public key:
+
+```bash
+$ openssl rsa -in <filename> -pubout > <filename>.pub
+```
+
+If key was generated by `ssh-keygen` the public key content is located in <filename>.pub and there is no need to extract public key
+
+#### Configure SSH authentication
+
 Configure seed job like:
 
 ```