Update .travis.yml

Author: hazzik

.travis.yml

@@ -13,6 +13,7 @@ env:
   - DB=MySQL CONNECTION_STRING="Server=127.0.0.1;Uid=root;Database=nhibernate;Old Guids=True;"   
   - DB=SQLite 
 before_install:
+  - sudo add-apt-repository -y ppa:mapopa/firebird3.0
   - sudo apt-get update -qq
   - sudo apt-get install -y powershell 
   - |-