Fix tiny_tds caused segfault

Author: Anna

Gemfile

@@ -27,7 +27,8 @@ group :tinytds do
   if ENV['TINYTDS_SOURCE']
     gem 'tiny_tds', :path => ENV['TINYTDS_SOURCE']
   else
-    gem 'tiny_tds', '~> 0.6.0'
+    #segfault caused by tiny_tds 0.6.1
+    gem 'tiny_tds', :git =>"https://github.com/rails-sqlserver/tiny_tds.git"
   end
 end