Level 4 not working as expected in Ubuntu 18.04

[sukreshmanda]

The solution for level4 should be just committing the README file that is already in the staging area. I did committed the staging area and git log shows that the commit is successful but the githug play is not accepting it as solution. I am attaching the screenshot of the issue.

[sukreshmanda]

I found that it is due to name of the branch. It works only when branch name is master. So change it to support any branch name.

[sukreshmanda]

In the level 16 also same problem.

[mamouneyya]

I had the exact same issue. Worked after creating a new branch with the name 'master'.

[IDontKnowWhy6]

I found that it is due to name of the branch. It works only when branch name is master. So change it to support any branch name.
Why can't I solve this problem on branch master?