Gem Load Error is: uninitialized constant Mysql2::Client::SECURE_CONNECTION on Ubuntu 16.04

While I am trying to create DB with rake db:create then I am getting this error:

rake aborted!
Bundler::GemRequireError: There was an error while trying to load the gem 'mysql2'.
Gem Load Error is: uninitialized constant Mysql2::Client::SECURE_CONNECTION
Backtrace for gem load error is:
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/mysql2-0.3.16/lib/mysql2/client.rb:12:in `<class:Client>'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/mysql2-0.3.16/lib/mysql2/client.rb:2:in `<module:Mysql2>'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/mysql2-0.3.16/lib/mysql2/client.rb:1:in `<top (required)>'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/mysql2-0.3.16/lib/mysql2.rb:10:in `require'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/mysql2-0.3.16/lib/mysql2.rb:10:in `<top (required)>'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/bundler-1.15.1/lib/bundler/runtime.rb:82:in `require'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/bundler-1.15.1/lib/bundler/runtime.rb:82:in `block (2 levels) in require'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/bundler-1.15.1/lib/bundler/runtime.rb:77:in `each'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/bundler-1.15.1/lib/bundler/runtime.rb:77:in `block in require'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/bundler-1.15.1/lib/bundler/runtime.rb:66:in `each'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/bundler-1.15.1/lib/bundler/runtime.rb:66:in `require'
/home/sachin/.rvm/gems/ruby-1.9.3-p545@oomph-sachin/gems/bundler-1.15.1/lib/bundler.rb:108:in `require'
/home/sachin/rails_projects/sachin/config/application.rb:8:in `<top (required)>'

Solution:

Update your Gemfile to version 0.3.20

     gem 'mysql2', '~> 0.3.20'

Then run "bundle update mysql2" and then try it will work!

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