Avoid setting fixed app name in console prompt

Instead, the app's name should be set via a separate IRB config, which
will allow it to be changed at runtime.

Co-authored-by: Mike Dalessio <mike.dalessio@gmail.com>

railties/lib/rails/commands/console/irb_console.rb

@@ -81,7 +81,8 @@ def start
 
         env = colorized_env
         app_name = @app.class.module_parent_name.underscore.dasherize
-        prompt_prefix = "#{app_name}(#{env})"
+        prompt_prefix = "%N(#{env})"
+        IRB.conf[:IRB_NAME] = app_name
 
         IRB.conf[:PROMPT][:RAILS_PROMPT] = {
           PROMPT_I: "#{prompt_prefix}> ",

railties/test/application/console_test.rb

@@ -110,6 +110,22 @@ def test_sandbox_by_default_with_development_environment
     @primary.puts "quit"
   end
 
+  def test_prompt_is_properly_set
+    options = "-e test"
+    spawn_console(options)
+
+    write_prompt "a = 1", "a = 1", prompt: "app-template(test)>"
+  end
+
+  def test_prompt_allows_changing_irb_name
+    options = "-e test"
+    spawn_console(options)
+
+    write_prompt "conf.irb_name = 'foo'"
+    write_prompt "a = 1", "a = 1", prompt: "foo(test)>"
+    @primary.puts "quit"
+  end
+
   def test_environment_option_and_irb_option
     options = "-e test -- --verbose"
     spawn_console(options)