Trying to start rails server in production environment - ruby-on-rails

Question

Rails server doesn't starting in production environment, i think that there is a conflict with databases, should i migrate them or smth else?
=> Booting Puma
=> Rails 5.0.6 application starting in production on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
Exiting
/home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activerecord-5.0.6/lib/active_record/connection_adapters/connection_specification.rb:170:in
`spec': database configuration does not specify adapter
(ActiveRecord::AdapterNotSpecified)
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activerecord-5.0.6/lib/active_record/connection_handling.rb:53:in `establish_connection'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activerecord-5.0.6/lib/active_record/railtie.rb:125:in `block (2 levels) in <class:Railtie>'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/lazy_load_hooks.rb:69:in `instance_eval'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/lazy_load_hooks.rb:69:in `block in execute_hook'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/lazy_load_hooks.rb:60:in `with_execution_control'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/lazy_load_hooks.rb:65:in `execute_hook'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/lazy_load_hooks.rb:41:in `block in on_load'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/lazy_load_hooks.rb:40:in `each'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.6/lib/active_support/lazy_load_hooks.rb:40:in `on_load'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activerecord-5.0.6/lib/active_record/railtie.rb:121:in `block in <class:Railtie>'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/initializable.rb:30:in `instance_exec'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/initializable.rb:30:in `run'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/initializable.rb:55:in `block in run_initializers'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:228:in `block in tsort_each'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:350:in `block (2 levels) in each_strongly_connected_component'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:431:in `each_strongly_connected_component_from'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:349:in `block in each_strongly_connected_component'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:347:in `each'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:347:in `call'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:347:in `each_strongly_connected_component'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:226:in `tsort_each'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/2.3.0/tsort.rb:205:in `tsort_each'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/initializable.rb:54:in `run_initializers'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/application.rb:352:in `initialize!'
from /home/user/Desktop/upgraded-carnival/config/environment.rb:5:in `<top (required)>'
from /home/user/Desktop/upgraded-carnival/config.ru:3:in `require_relative'
from /home/user/Desktop/upgraded-carnival/config.ru:3:in `block in <main>'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/builder.rb:55:in `instance_eval'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/builder.rb:55:in `initialize'
from /home/user/Desktop/upgraded-carnival/config.ru:in `new'
from /home/user/Desktop/upgraded-carnival/config.ru:in `<main>'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/builder.rb:49:in `eval'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/builder.rb:49:in `new_from_string'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/builder.rb:40:in `parse_file'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/server.rb:319:in `build_app_and_options_from_config'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/server.rb:219:in `app'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/commands/server.rb:84:in `app'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/server.rb:354:in `wrapped_app'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/rack-2.0.3/lib/rack/server.rb:283:in `start'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/commands/server.rb:104:in `start'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/commands/commands_tasks.rb:90:in `block in server'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/commands/commands_tasks.rb:85:in `tap'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/commands/commands_tasks.rb:85:in `server'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
from /home/user/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.6/lib/rails/commands.rb:18:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
My database.yml :
default: &default
adapter: postgresql
encoding: unicode
pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
production:
host: localhost
database: magnetcoin_production
pool: 10
timeout: 10000
username: magnetcoin
password:
magnetcoin template: template0
development: <<: *default
database: magnetcoin_development
test: <<: *default
database: magnetcoin_test

Answer 1

As per you logs you did not define the adaptor for your production env database config. You added the adaptor in default block but did not import default to production block. Just import default block in production block and every thing works fine.
default: &default
adapter: postgresql
encoding: unicode
pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
production: <<: *default
host: localhost
database: magnetcoin_production
pool: 10
timeout: 10000
username: magnetcoin
password: magnetcoin
template: template0
development: <<: *default
database: magnetcoin_development
test: <<: *default
database: magnetcoin_test