Add tag logging example

README.md

@@ -116,7 +116,7 @@ encouraged. In cases where the data is meaningful, consider [logging a custom ev
 
 Use `Logger` as normal:
 
-```elixir
+```ruby
 logger.info("My log message")
 
 # My log message @metadata {"level": "info", "context": {...}}
@@ -128,6 +128,35 @@ Timber will never deviate from the public `::Logger` interface in *any* way.
 
 </p></details>
 
+<details><summary><strong>Tagging logs</strong></summary><p>
+
+Need a quick and easy way to identify a log? Use tags!:
+
+```ruby
+logger.info(message: "My log message", tag: "tag")
+# My log message @metadata {"level": "info", "tags": ["tag"], "context": {...}}
+```
+
+Multiple tags:
+
+```ruby
+logger.info(message: "My log message", tags: ["tag1", "tag2"])
+
+# My log message @metadata {"level": "info", "tags": ["tag1", "tag2"], "context": {...}}
+```
+
+Using `ActiveSupport::TaggedLogging`? It works with that as well:
+
+```ruby
+logger.tagged("tag") do
+  logger.info(message: "My log message", tags: ["important", "slow"])
+end
+
+# My log message @metadata {"level": "info", "tags": ["tag"], "context": {...}}
+```
+
+</p></details>
+
 <details><summary><strong>Custom events</strong></summary><p>
 
 1. Log a structured Hash (simplest)

lib/timber/logger.rb

@@ -77,6 +77,7 @@ def build_log_entry(severity, time, progname, msg)
           level = SEVERITY_MAP.fetch(severity)
           context_snapshot = CurrentContext.instance.snapshot
           tags = extract_active_support_tagged_logging_tags
+          tags += [msg.delete(:tag)] if msg.is_a?(Hash) && msg.key?(:tag)
           tags += msg.delete(:tags) if msg.is_a?(Hash) && msg.key?(:tags)
           event = Events.build(msg)