Fixed #323 Allow users to select a language in settings (GRN-17) (#324)

* <Added ui for language setting and migration>

* <Option to choose languages added>

* <Fixed code style>

* <Added Rspec tests>

* <sync db>

* <Sync db>

* <Generalized language settings>

* <Fixed flash message>

* Fixed las issue with i18n fallback

* <Modified fallback config>

* <Fixed code style>

app/views/users/edit.html.erb

@@ -19,7 +19,7 @@
   <div class="row">
     <div class="col-lg-3 mb-4">
       <div class="list-group list-group-transparent mb-0">
-        
+
         <button id="account" class="list-group-item list-group-item-action setting-btn <%= "active" if !params[:setting] || params[:setting] == "account"%>">
           <span class="icon mr-3"><i class="fas fa-user"></i></span><%= t("settings.account.title") %>
         </button>