Jujutsu/git integration

The editor now has a button to commit changes to a Jujutsu repository,
which is automatically created if it's not present.

A git remote is automatically set up using the URL template in
settings.py. I use this with Forgejo's create-on-push feature to
automatically create repositories on my Forgejo instance.

thinks/forms.py

@@ -127,3 +127,10 @@ class RunCommandForm(forms.ModelForm):
     class Meta:
         model = Think
         fields = []
+
+class GitCommitForm(forms.ModelForm):
+    message = forms.CharField()
+
+    class Meta:
+        model = Think
+        fields = []