Elaborate on github.username and github.login.

Fixes #130.

docs/source/configuration.rst

@@ -80,10 +80,15 @@ Example Configuration
     # or not."
     [my_github]
     service = github
-    github.username = ralphbean
     default_priority = H
     add_tags = open_source
     
+    # This specifies that we should pull issues from repositories belonging
+    # to the 'ralphbean' github account.  See the note below about
+    # 'github.username' and 'github.login'.  They are different, and you need
+    # both.
+    github.username = ralphbean
+    
     # I want taskwarrior to include issues from all my repos, except these
     # two because they're spammy or something.
     github.exclude_repos = project_bar,project_baz
@@ -92,8 +97,13 @@ Example Configuration
     # can also simply include just a limited set.
     github.include_repos = project_foo,project_foz
     
-    # Note that login and username can be different.  I can login as me, but
+    # Note that login and username can be different:  I can login as me, but
     # scrape issues from an organization's repos.
+    #
+    # - 'github.login' is the username you ask bugwarrior to
+    #   login as.  Set it to your account.
+    # - 'github.username' is the github entity you want to pull
+    #   issues for.  It could be you, or some other user entirely.
     github.login = ralphbean
     github.password = OMG_LULZ
     

docs/source/services/github.rst

@@ -11,6 +11,7 @@ Here's an example of an Github target::
 
     [my_issue_tracker]
     service = github
+    github.username = ralphbean
     github.login = ralphbean
     github.password = OMG_LULZ
 
@@ -19,6 +20,14 @@ Github.  You can also feel free to use any of the
 configuration options described in :ref:`common_configuration_options`
 or described in `Service Features`_ below.
 
+Note that both ``github.username`` and ``github.login`` are required and can be
+set to different values.  ``github.login`` is used to specify what account
+bugwarrior should use to login to github.  ``github.username`` indicates which
+repositories should be scraped.  For instance, I always have ``github.login``
+set to ralphbean (my account).  But I have some targets with
+``github.username`` pointed at organizations or other users to watch issues
+there.
+
 Service Features
 ----------------