Add RSwag coverage for /chat and /transactions API endpoints (#210)

* Add RSwag coverage for chat API

* Linter

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: Juan José Mata <jjmata@jjmata.com>

* Add transaction rswag

* FIX linter

---------

Signed-off-by: Juan José Mata <jjmata@jjmata.com>
Signed-off-by: Juan José Mata <juanjo.mata@gmail.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: sokie <sokysrm@gmail.com>

Gemfile

@@ -123,4 +123,8 @@ group :test do
   gem "webmock"
   gem "climate_control"
   gem "simplecov", require: false
+  gem "rspec-rails"
+  gem "rswag-api"
+  gem "rswag-specs"
+  gem "rswag-ui"
 end