Create standard SVN layout
README explaining the purpose of the repo
Ignore *.html
Add a custom .gitignore file

This simulates the case of a git-svn user wishing to ignore *.txt
files, without adding them to Subversion's native svn:ignore property.
Branch trunk to cool-feature

This causes reposurgeon to replace the custom .gitignore with only the
contents of svn:ignore.
Explain what the expected result should be.
Merge cool-feature back to trunk
Explain the final expected result.