labhub: Adapt to the modified newcomer process

- `invite me` variation of invite command is removed.
- "Hello world"s no longer trigger invites.
- Newcomer invitation message is changed to show the modification in the
  newcomer process.

Closes #476

plugins/labhub.py

@@ -17,10 +17,11 @@ class LabHub(BotPlugin):
     """GitHub and GitLab utilities"""  # Ignore QuotesBear
 
     INVITE_SUCCESS = {
-        'newcomers': 'Welcome @{}! :tada:\n\nWe\'ve just sent you an invite'
-                     ' via email. Please accept it before proceeding forward.'
-                     '\nTo get started, please follow our [newcomers guide]'
-                     '(https://coala.io/newcomer). Most '
+        'newcomers': 'Welcome @{}! :tada:\n\n'
+                     'Please go through https://coala.io/newcomer (skip '
+                     'instructions about using corobo). Find your first issue '
+                     'and ask one of the maintainers to assign you to it and '
+                     'we\'ll invite you to the org. Most '
                      'issues will be explained there and in linked pages - it '
                      'will save you a lot of time, just read it. *Really.*\n\n'
                      '*Do not take an issue if you don\'t understand it on '
@@ -106,13 +107,6 @@ def invite_cmd(self, msg, match):
         invitee = match.group(1)
         inviter = msg.frm.nick
 
-        if invitee == 'me':
-            user = msg.frm.nick
-            self.send(msg.frm, self.INVITE_SUCCESS['newcomers'].format(user))
-            self.TEAMS[self.GH_ORG_NAME + ' newcomers'].invite(user)
-            self.invited_users.add(user)
-            return
-
         team = 'newcomers' if match.group(2) is None else match.group(2)
 
         self.log.info('{} invited {} to {}'.format(inviter, invitee, team))
@@ -143,8 +137,6 @@ def callback_message(self, msg):
                 # send the invite
                 self.send(msg.frm,
                           self.INVITE_SUCCESS['newcomers'].format(user))
-                self.TEAMS[self.GH_ORG_NAME + ' newcomers'].invite(user)
-                self.invited_users.add(user)
 
     @re_botcmd(pattern=r'(?:new|file) issue ([\w\-\.]+?)(?: |\n)(.+?)(?:$|\n((?:.|\n)*))',  # Ignore LineLengthBear, PyCodeStyleBear
                re_cmd_name_help='new issue repo-name title\n[description]',