Add test for AR Model.create instantiations

These currently aren't recognised.

Author: hmac

ruby/ql/test/library-tests/frameworks/active_record/ActiveRecord.expected

@@ -135,6 +135,7 @@ activeRecordModelClassMethodCalls
 | ActiveRecord.rb:72:5:72:24 | call to create |
 | ActiveRecord.rb:76:5:76:66 | call to create |
 | ActiveRecord.rb:80:5:80:68 | call to create |
+| ActiveRecord.rb:84:5:84:16 | call to create |
 | ActiveRecord.rb:88:5:88:27 | call to update |
 | ActiveRecord.rb:92:5:92:69 | call to update |
 | ActiveRecord.rb:96:5:96:71 | call to update |

ruby/ql/test/library-tests/frameworks/active_record/ActiveRecord.rb

@@ -81,7 +81,7 @@ def create3
   end
 
   def create4
-
+    Admin.create
   end
 
   def update1