[core] Tracer#set_tags accepts a hash instead of a single key

lib/ddtrace/contrib/rails/framework.rb

@@ -60,7 +60,7 @@ def self.configure(config)
             Datadog::Ext::AppTypes::CACHE
           )
 
-          datadog_config[:tracer].set_tag('env', datadog_config[:env])
+          datadog_config[:tracer].set_tags('env' => datadog_config[:env])
 
           if defined?(::ActiveRecord)
             begin

lib/ddtrace/tracer.rb

@@ -95,11 +95,9 @@ def set_service_info(service, app, app_type)
     # appended to each span created by the tracer. Keys and values must be strings.
     # A valid example is:
     #
-    #   tracer.set_tag('env', 'prod')
-    def set_tag(key, value)
-      @tags[key] = value.to_s
-    rescue StandardError => e
-      Datadog::Tracer.log.debug("Unable to set the tag #{key}, ignoring it. Caused by: #{e}")
+    #   tracer.set_tags('env' => 'prod', 'component' => 'core')
+    def set_tags(tags)
+      @tags.update(tags)
     end
 
     # Return a +span+ that will trace an operation called +name+. You could trace your code

test/tracer_test.rb

@@ -102,17 +102,19 @@ def test_set_service_info
     assert_equal(tracer.services['rest-api'], 'app' => 'rails', 'app_type' => 'web')
   end
 
-  def test_set_tag
+  def test_set_tags
     tracer = get_test_tracer
-    tracer.set_tag('env', 'test')
+    tracer.set_tags('env' => 'test', 'component' => 'core')
     assert_equal(tracer.tags['env'], 'test')
+    assert_equal(tracer.tags['component'], 'core')
   end
 
   def test_trace_global_tags
     tracer = get_test_tracer
-    tracer.set_tag('env', 'test')
+    tracer.set_tags('env' => 'test', 'component' => 'core')
     span = tracer.trace('something')
     assert_equal(span.get_tag('env'), 'test')
+    assert_equal(span.get_tag('component'), 'core')
   end
 
   def test_disabled_tracer