add support for mysql2 adapter to dbconsole

[#4532 state:committed]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

railties/lib/rails/commands/dbconsole.rb

@@ -55,7 +55,7 @@ def find_cmd(*commands)
       end
 
       case config["adapter"]
-      when "mysql"
+      when /^mysql/
         args = {
           'host'      => '--host',
           'port'      => '--port',