Add a support for pip unknown commands

thefuck/rules/pip_unknown_command.py

@@ -0,0 +1,15 @@
+import re
+
+
+def match(command, settings):
+    return ('pip' in command.script and
+            'unknown command' in command.stderr and
+            'maybe you meant' in command.stderr)
+
+
+def get_new_command(command, settings):
+    broken_cmd = re.findall(r'ERROR: unknown command \"([a-z]+)\"',
+                            command.stderr)[0]
+    new_cmd = re.findall(r'maybe you meant \"([a-z]+)\"', command.stderr)[0]
+
+    return command.script.replace(broken_cmd, new_cmd, 1)