Add git_two_dashes rule

thefuck/rules/git_two_dashes.py

@@ -0,0 +1,14 @@
+from thefuck.utils import replace_argument
+from thefuck.specific.git import git_support
+
+
+@git_support
+def match(command):
+    return ('error: did you mean `' in command.stderr
+            and '` (with two dashes ?)' in command.stderr)
+
+
+@git_support
+def get_new_command(command):
+    to = command.stderr.split('`')[1]
+    return replace_argument(command.script, to[1:], to)