Fix PG12 tests and add PG12 to travis (#78)

Author: Burak Yücesoy

.travis.yml

@@ -1,5 +1,5 @@
 sudo: required
-dist: trusty
+dist: bionic
 language: c
 env:
   global:
@@ -12,8 +12,9 @@ matrix:
     - env: PGVERSION=9.6
     - env: PGVERSION=10
     - env: PGVERSION=11
+    - env: PGVERSION=12
 before_install:
-  - git clone -b v0.7.9 --depth 1 https://github.com/citusdata/tools.git
+  - git clone -b v0.7.12 --depth 1 https://github.com/citusdata/tools.git
   - sudo make -C tools install
   - setup_apt
   - nuke_pg
@@ -22,4 +23,6 @@ install:
   - install_pg
 before_script:
   - config_and_start_cluster
+  - echo "extra_float_digits = 0" >> "/etc/postgresql/${PGVERSION}/test/postgresql.conf"
+  - pg_ctlcluster "${PGVERSION}" test restart
 script: pg_travis_test