Use trusty in travis (#3170)

* Use trusty in travis

* Install postgresql-9.5-postgis-2.3 in travis

.travis.yml

@@ -1,6 +1,5 @@
 language: node_js
-dist: precise
-sudo: false
+dist: trusty
 node_js:
 - '4.5'
 - '6.1'
@@ -10,6 +9,8 @@ services:
   - docker
 addons:
   postgresql: '9.5'
+  apt_packages:
+  - postgresql-9.5-postgis-2.3
 before_script:
   - ls -al "$HOME/.mongodb/versions"
   - psql -c 'create database parse_server_postgres_adapter_test_database;' -U postgres