[Travis] It takes root perms to edit postgresql.conf

.travis.yml

@@ -12,8 +12,8 @@ before_install:
     cd pg_schema_triggers && make && sudo make install && cd -
   # Preload schema_triggers module
   # NOTE: might change if we make it part of the installcheck instead
-  - echo "local_preload_libraries = 'schema_triggers.so'" >> 
-    /etc/postgresql/9.3/main/postgresql.conf &&
+  - echo "local_preload_libraries = 'schema_triggers.so'" |
+    sudo tee -a /etc/postgresql/9.3/main/postgresql.conf &&
     sudo service postgresql restart
 
 script: