Use Heroku cloud service on Ubuntu to publish Rails Applications with databases

The program initially uses the sqlite3 database. Modify the Gemfile file to add the Support group: productiondo # gemsspecificallyforHerokugoheregem "pg" endbundleinstall to the heroku deployment to pre-compile some files. Otherwise, the bundleexecrakeassets will error on heroku:

The program initially uses the sqlite3 database.

Modify the Gemfile file, and add pg support to heroku deployment
Group: production do
# Gems specifically for Heroku go here
Gem "pg"
End

Bundle install

Pre-compile some files; otherwise, an error occurs on heroku.

Bundle exec rake assets: precompile

Publish the application to Github.

$ Git add.
$ Git commit-a-m "Done with the demo app"
Done with the demo app, add heroku pg database support
$ Git push

Publish the application to the heroku Server
$ Heroku create
$ Git push heroku master
$ Heroku rake db: migrate

$ Heroku rename BerryreloadDemoApp

Now I can test my database application on heroku ECS.

Refer:

Use Heroku cloud service on Ubuntu to publish a Rails Application

If you execute the command

$ Bundle exec rake assets: precompile

The following error is reported:
Rake aborted!
Undefined method 'prerequisites 'for nil: NilClass
(See full trace by running task with -- trace)

Execute the command again

$ Bundle exec rake assets: precompile -- trace

The following error is reported:

Rake aborted!
Undefined method 'prerequisites 'for nil: NilClass
/Usr/local/ruby/lib/ruby/gems/1.9.1/gems/rspec-rails-2.0.1/lib/rspec/rails/tasks/rspec. rake: 3: in' '

The conclusion is that rspec-rails-2.0.1 and rake, Rails 3.1.3 are incompatible and need to be upgraded

Upgrade Method:

Modify the Gemfile of the project and remove the rspec-rails version. If you set the rspec-Rails version based on the Tutorial Ruby on rails 3 Tutorial.

Group: development do
Gem 'rspec-rails'
End

Group: test do
Gem 'rspec'
Gem 'webrat'
End

Finally, execute the command

$ Bundle update rspec-rails

The result shows the upgrade to rspec-rails 2.8.1.

The command is successfully executed again.

$ Bundle exec rake assets: precompile

Then,

$ Git add.

$ Git commit-am "Done with static pages and precompile for heroku"

$ Git push

$ Git push heroku

$ Heroku rake db: migrate