Redmine

When I first setup Redmine 3.0.4, it was on Ubuntu 14.04 with Nginx and Puma. Then I upgraded the server to Ubuntu 15.04, and now I am getting a 502 Bad Gateway. I've tried everything I can think of. Has anyone else been through a similar situation? Can you help me troubleshoot what the issue may be?

ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
Rails 4.2.3
MariaDB 10.x
Ubuntu 15.04
Puma

Below is the last thing that I've tried:

root@puritan:/etc/nginx/sites-available# /etc/init.d/redmine start
Puma starting in single mode...
* Version 2.12.0 (ruby 2.1.2-p95), codename: Plutonian Photo Shoot
* Min threads: 0, max threads: 16
* Environment: production
* Daemonizing...
root@puritan:/etc/nginx/sites-available# /etc/init.d/redmine restart
Couldn't restart

When running the following command RAILS_ENV=production bin/about, I get the following error:

/home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:274:in `require': libmariadbclient.so.18: cannot open shared object file: No such file or directory - /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/extensions/x86_64-linux/2.1.0-static/mysql2-0.3.18/mysql2/mysql2.so (LoadError)
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:274:in `block in require'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:240:in `load_dependency'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/activesupport-4.2.3/lib/active_support/dependencies.rb:274:in `require'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/mysql2-0.3.18/lib/mysql2.rb:31:in `<top (required)>'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/bundler-1.10.5/lib/bundler/runtime.rb:76:in `require'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/bundler-1.10.5/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/bundler-1.10.5/lib/bundler/runtime.rb:72:in `each'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/bundler-1.10.5/lib/bundler/runtime.rb:72:in `block in require'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/bundler-1.10.5/lib/bundler/runtime.rb:61:in `each'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/bundler-1.10.5/lib/bundler/runtime.rb:61:in `require'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/bundler-1.10.5/lib/bundler.rb:134:in `require'
    from /home/redmine/redmine/config/application.rb:5:in `<top (required)>'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /home/redmine/redmine/config/environment.rb:2:in `<top (required)>'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /home/redmine/.rbenv/versions/2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from bin/about:4:in `<main>'

Gem List:

actionmailer (4.2.3)
actionpack (4.2.3)
actionpack-action_caching (1.1.1)
actionpack-xml_parser (1.0.2)
actionview (4.2.3)
activejob (4.2.3)
activemodel (4.2.3)
activerecord (4.2.3)
activesupport (4.2.3)
acts-as-taggable-on (3.5.0, 2.4.1)
arel (6.0.2)
awesome_nested_set (3.0.2)
bigdecimal (1.2.4)
builder (3.2.2)
bundler (1.10.5)
coderay (1.1.0)
erubis (2.7.0)
globalid (0.3.5)
httpclient (2.6.0.1)
i18n (0.7.0)
io-console (0.4.2)
jquery-rails (3.1.3)
json (1.8.3, 1.8.1)
loofah (2.0.2)
mail (2.6.3)
mime-types (2.6.1)
mini_portile (0.6.2)
minitest (5.7.0, 4.7.5)
mysql2 (0.3.18)
net-ldap (0.3.1)
nokogiri (1.6.6.2)
protected_attributes (1.1.3)
psych (2.0.5)
puma (2.12.0)
rack (1.6.4)
rack-openid (1.4.2)
rack-test (0.6.3)
rails (4.2.3)
rails-deprecated_sanitizer (1.0.3)
rails-dom-testing (1.0.6)
rails-html-sanitizer (1.0.2)
railties (4.2.3)
rake (10.4.2, 10.1.0)
rbpdf (1.18.6)
rdoc (4.1.0)
redcarpet (3.1.2)
redmine_acts_as_taggable_on (1.0.0)
request_store (1.0.5)
rmagick (2.13.4)
ruby-mysql (2.9.13)
ruby-openid (2.3.0)
rubyzip (1.1.7)
slim (3.0.6)
sprockets (3.2.0)
sprockets-rails (2.3.2)
temple (0.7.6)
test-unit (2.1.2.0)
thor (0.19.1)
thread_safe (0.3.5)
tilt (2.0.1)
tzinfo (1.2.2)
ya2yaml (0.31)