Add git_branch_delete rule

thefuck/rules/git_branch_delete.py

@@ -0,0 +1,7 @@
+def match(command, settings):
+    return ('git branch -d' in command.script
+            and 'If you are sure you want to delete it' in command.stderr)
+
+
+def get_new_command(command, settings):
+    return command.script.replace('-d', '-D')