title: Symfony 1.4.4 - Doctrine migration and Plugin installation
body: <p>I make my first steps in the symfony plugin world, and I'm a bit 
  lost... </p>
  
  <p>I have a live app with a database. Usually, when I need a new table or 
  field I do a migration, by updating my schema.yml, calling the 
  generate-migration-diff and build --all-classes --and-migrate symfony 
  commands. </p>
  
  <p>Today, I need to install a plugin (i.e, sfCombinePlugin) in order to 
  minify my js and css scripts. I installed it via the symfony 
  plugin:install command, it's ok I've got all my files in the plugins 
  folder. I follow the read-me, it says to build the model, so I run the 
  command doctrine:build-model, and a folder sfCombinePlugin appears in 
  my lib/model/doctrine folder. </p>
  
  <p>But now I'm stuck, I need to add the table in my database. In the read- 
  me it says, to generate the sql via doctrine:build-sql, and run the 
  generated sql in my database. But I see some issues coming... </p>
  
  <p>Will it erase my data by running the sql file? I pretty sure it will, 
  because it create the database from scratch... </p>
  
  <p>So, I would like to use a migration, as I do usually. But when I run 
  the generate-migration-diff, it doesn't take in account the schema.yml 
  from the plugin folder. Is it normal or is it a bug? </p>
  
  <p>I've thought of copying the content of the schema.yml plugin inside 
  the schema.yml app file, but I'm not sure this is a good idea, because 
  the model classes will not be in the sfCombinePlugin folder but in the 
  general model folder. And it sounds not good. </p>