Merge remote-tracking branch 'upstream/pull/2473'

diff --combined .travis.yml
index db9128412bc006d921684bd2764af1725293debf,fbb8b46ab0c2cb26e46464e9f784f0e984b3688e..b950b1e18e2cbf8083078758a08702d7493c267a
--- 1/.travis.yml
--- 2/.travis.yml
+++ b/.travis.yml
@@@ -1,4 -1,4 +1,4 @@@
- dist: xenial
+ dist: bionic
  language: ruby
  rvm:
    - 2.5.3
@@@ -9,8 -9,14 +9,11 @@@ addons
    apt:
      packages:
        - libarchive-dev
+       - libgd-dev
+       - libffi-dev
+       - libbz2-dev
  services:
    - memcached
 -env:
 -  global:
 -    - OSM_MEMCACHE_SERVERS="127.0.0.1"
  before_script:
    - sed -e 's/ IMMUTABLE / /' -e "/^--/d" db/structure.sql > db/structure.expected
    - psql -U postgres -c "CREATE DATABASE openstreetmap"
@@@ -18,7 -24,7 +21,7 @@@
    - psql -U postgres -f db/functions/functions.sql openstreetmap
    - cp config/travis.database.yml config/database.yml
    - cp config/example.storage.yml config/storage.yml
 -  - touch config/settings.local.yml
 +  - echo -e "---\nmemcache_servers:\n  - 127.0.0.1" > config/settings.local.yml
    - bundle exec rake db:migrate
    - bundle exec rake i18n:js:export
    - bundle exec rake yarn:install