Try to get postgres logs when tests deadlock

.travis.yml

@@ -22,12 +22,15 @@ before_script:
 
 script:
   - cargo build
-  - cargo test -- --test-threads=1
+  - cargo test
   - yarn run test
 
 after_success:
   - travis-cargo coveralls --no-sudo
 
+after_failure:
+  - tail -100 /var/log/postgresql/postgresql-*-main.log
+
 addons:
   postgresql: "9.3"
   apt: