add JJController.ignore_paths back in

thinks/jujutsu.py

@@ -34,6 +34,23 @@ class JJController:
             git_url = settings.GIT_REPO_URL_TEMPLATE.format(name=self.think.slug)
             self.run(['jj','git','remote','add','origin', git_url])
 
+    @ensure_jj
+    def ignore_paths(self, paths):
+        paths = self.clean_paths(paths)
+        gitignore = self.root / '.gitignore'
+        if len(paths) == 0:
+            return
+
+        if gitignore.exists():
+            with open(gitignore) as f:
+                ignored = f.read().strip().split('\n')
+            ignored += [p for p in paths if p not in ignored]
+        else:
+            ignored = paths
+
+        with open(gitignore, 'w') as f:
+            f.write('\n'.join(ignored))
+
     @ensure_jj
     def status(self):
         res = self.run(['jj','st'])