Repository: railwayapp/nixpacks (rust)

Issue:
Add RAILS_LOG_TO_STDOUT=enabled by default to RoR projects 
### Feature request

Some Ruby projects doesn't send application logs to stdout once started.
`RAILS_LOG_TO_STDOUT=enabled ` should fix the issue

It would be better to have it as the default behavior!

### Motivation

_No response_

### Contribution

_No response_

Pull request description:
feat: enable `RAILS_LOG_TO_STDOUT`
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This PR sets `RAILS_LOG_TO_STDOUT=enabled` if ruby on rails app is detected.

Fixes #559 
<!-- PR Checklist  -->
- [x] Tests are added/updated if needed
<!-- - [ ] Docs are updated if needed  -->

Patch:
diff --git a/src/providers/ruby.rs b/src/providers/ruby.rs
index 42b2433..bd72135 100644
--- a/src/providers/ruby.rs
+++ b/src/providers/ruby.rs
@@ -114,7 +114,7 @@ impl RubyProvider {
 
     fn get_environment_variables(&self, app: &App) -> Result<EnvironmentVariables> {
         let ruby_version = self.get_ruby_version(app)?;
-        Ok(EnvironmentVariables::from([
+        let mut env_vars = EnvironmentVariables::from([
             ("BUNDLE_GEMFILE".to_string(), "/app/Gemfile".to_string()),
             (
                 "GEM_PATH".to_string(),
@@ -127,7 +127,11 @@ impl RubyProvider {
                 "GEM_HOME".to_string(),
                 format!("/usr/local/rvm/gems/{}", ruby_version),
             ),
-        ]))
+        ]);
+        if self.is_rails_app(app) {
+            env_vars.insert("RAILS_LOG_TO_STDOUT".to_string(), "enabled".to_string());
+        }
+        Ok(env_vars)
     }
 
     fn get_start_command(&self, app: &App) -> Option<String> {


Test patch:
diff --git a/tests/snapshots/generate_plan_tests__ruby_rails_postgres.snap b/tests/snapshots/generate_plan_tests__ruby_rails_postgres.snap
index 1314f36..14ba927 100644
--- a/tests/snapshots/generate_plan_tests__ruby_rails_postgres.snap
+++ b/tests/snapshots/generate_plan_tests__ruby_rails_postgres.snap
@@ -9,7 +9,8 @@ expression: plan
     "BUNDLE_GEMFILE": "/app/Gemfile",
     "GEM_HOME": "/usr/local/rvm/gems/3.1.2",
     "GEM_PATH": "/usr/local/rvm/gems/3.1.2:/usr/local/rvm/gems/3.1.2@global",
-    "NIXPACKS_METADATA": "Ruby"
+    "NIXPACKS_METADATA": "Ruby",
+    "RAILS_LOG_TO_STDOUT": "enabled"
   },
   "phases": {
     "build": {