I personally use the
file upload plugin to send individual tiddlers to GitHub, I made a button for it on my wiki :
https://Telumire.github.io/TiddlyTweaks/index.html#:%5B%5BSend%20tiddler%20with%20file%20upload%5D%5D\whitespace trim
\define tiddler-attr()[[$(currentTiddler)$]]
<$button class="tc-btn-invisible" tooltip="send this tiddler with file upload">
<$list filter="[<tv-config-toolbar-icons>match[yes]]+[<currentTiddler>!has[_canonical_uri]]" variable=_>
{{$:/plugins/commons/file-uploads/images/upload}}
<$action-sendmessage $message="tm-upload-tiddlers" $param=<<tiddler-attr>> />
</$list>
<$list filter="[<tv-config-toolbar-icons>match[yes]]+[<currentTiddler>has[_canonical_uri]]" variable=_>
<a class="tc-tiddlylink" title="open source file" href={{{[<_>get[_canonical_uri]]}}}>{{$:/core/images/globe}}</a>
</$list>
<$list filter="[<tv-config-toolbar-text>match[yes]]">
<span class="tc-btn-text">
<$text text=" "/>
<$text text="Send with file upload"/>
</span>
</$list>
</$button>
However the plugin will delete the content of your tiddler and attempt to link to the hosted file trough the
_canonical_uri field, so I use it only for image tiddlers.
I'm sure you can find a workaround ?