Remove skip_migrations and introduce database and skip_adapter on install

We never want to skip the migrations but we might want to skip setting
the adapter if we're moving from another Active Job backend. Also, add a
`database` option to select a different DB from the main one when
copying the migrations.

Author: rosa

README.md

@@ -31,9 +31,9 @@ $ bin/rails generate solid_queue:install
 
 This will set `solid_queue` as the Active Job's adapter in production, and will copy the required migration over to your app.
 
-Alternatively, you can add only the migration to your app:
+Alternatively, you can skip setting the Active Job's adapter with:
 ```bash
-$ bin/rails solid_queue:install:migrations
+$ bin/rails generate solid_queue:install --skip_adapter
 ```
 
 And set Solid Queue as your Active Job's queue backend manually, in your environment config:
@@ -42,7 +42,7 @@ And set Solid Queue as your Active Job's queue backend manually, in your environ
 config.active_job.queue_adapter = :solid_queue
 ```
 
-Alternatively, you can set only specific jobs to use Solid Queue as their backend if you're migrating from another adapter and want to move jobs progressively:
+Or you can set only specific jobs to use Solid Queue as their backend if you're migrating from another adapter and want to move jobs progressively:
 
 ```ruby
 # app/jobs/my_job.rb
@@ -194,13 +194,13 @@ development:
     # ...
 ```
 
-Install migrations and specify the dedicated database name with the `DATABASE` option. This will create the Solid Queue migration files in a separate directory, matching the value provided in `migrations_paths` in `config/database.yml`.
+Install migrations and specify the dedicated database name with the `--database` option. This will create the Solid Queue migration files in a separate directory, matching the value provided in `migrations_paths` in `config/database.yml`.
 
 ```bash
-$ bin/rails solid_queue:install:migrations DATABASE=solid_queue
+$ bin/rails g solid_queue:install --database solid_queue
 ```
 
-Note: If you've already run the solid queue install command (`bin/rails generate solid_queue:install`), the migration files will have already been generated under the primary database's `db/migrate/` directory. You can remove these files and keep the ones generated by the database-specific migration installation above.
+Note: If you've already run the solid queue install command (`bin/rails generate solid_queue:install`) without a `--database` option, the migration files will have already been generated under the primary database's `db/migrate/` directory. You can remove these files and keep the ones generated by the database-specific migration installation above.
 
 Finally, run the migrations:
 

lib/generators/solid_queue/install/install_generator.rb

@@ -3,19 +3,25 @@
 class SolidQueue::InstallGenerator < Rails::Generators::Base
   source_root File.expand_path("templates", __dir__)
 
-  class_option :skip_migrations, type: :boolean, default: nil, desc: "Skip migrations"
+  class_option :skip_adapter, type: :boolean, default: nil, desc: "Skip setting Solid Queue as the Active Job's adapter"
+  class_option :database, type: :string, default: nil, desc: "The database to use for migrations, if different from the primary one."
 
   def add_solid_queue
-    if (env_config = Pathname(destination_root).join("config/environments/production.rb")).exist?
-      gsub_file env_config, /(# )?config\.active_job\.queue_adapter\s+=.*/, "config.active_job.queue_adapter = :solid_queue"
+    unless options[:skip_adapter]
+      if (env_config = Pathname(destination_root).join("config/environments/production.rb")).exist?
+        say "Setting solid_queue as Active Job's queue adapter"
+        gsub_file env_config, /(# )?config\.active_job\.queue_adapter\s+=.*/, "config.active_job.queue_adapter = :solid_queue"
+      end
     end
 
+    say "Copying sample configuration"
     copy_file "config.yml", "config/solid_queue.yml"
   end
 
   def create_migrations
-    unless options[:skip_migrations]
-      rails_command "railties:install:migrations FROM=solid_queue", inline: true
-    end
+    say "Installing database migrations"
+    arguments = [ "FROM=solid_queue" ]
+    arguments << "DATABASE=#{options[:database]}" if options[:database].present?
+    rails_command "railties:install:migrations #{arguments.join(" ")}", inline: true
   end
 end

solid_queue.gemspec

@@ -11,15 +11,16 @@ Gem::Specification.new do |spec|
   spec.license     = "MIT"
 
   spec.post_install_message = <<~MESSAGE
-    Upgrading to Solid Queue 0.4.x? There are some breaking changes about how Solid Queue is started. Check
-    https://github.com/rails/solid_queue/blob/main/UPGRADING.md for upgrade instructions.
+    Upgrading to Solid Queue 0.4.x? There are some breaking changes about how Solid Queue is started,
+    configuration and new migrations. Check https://github.com/rails/solid_queue/blob/main/UPGRADING.md
+    for upgrade instructions.
   MESSAGE
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = "https://github.com/rails/solid_queue"
 
   spec.files = Dir.chdir(File.expand_path(__dir__)) do
-    Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md"]
+    Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md", "UPGRADING.md"]
   end
 
   rails_version = ">= 7.1"