Prioritize hash in connection parameter detection

Allow to detect hashes responding to `#call`, like
`ActiveSupport::OrderedOptions`

This will enable out of the box compatibility with
`Rails.application.config_for` method and should not break existing
use cases

Close leandromoreira#152

lib/redlock/client.rb

@@ -160,17 +160,12 @@ class RedisInstance
       def initialize(connection)
         @monitor = Monitor.new
 
-        if connection.respond_to?(:call)
-          @redis = connection
-        else
-          if connection.respond_to?(:client)
-            @redis = connection
-          elsif connection.respond_to?(:key?)
-            @redis = initialize_client(connection)
+        @redis =
+          if connection.is_a?(Hash)
+            initialize_client(connection)
           else
-            @redis = connection
+            connection
           end
-        end
       end
 
       def initialize_client(options)

spec/client_spec.rb

@@ -65,6 +65,20 @@
       lock_manager.unlock(lock_info)
     end
 
+    it 'accepts hashes responding to call like ActiveSupport::OrderedOptions' do
+      callable_hash = Class.new(Hash) do
+        def call; end
+      end
+
+      config = callable_hash.new.merge(url: "redis://#{redis1_host}:#{redis1_port}")
+      redlock = Redlock::Client.new([config])
+
+      lock_info = redlock.lock(resource_key, ttl)
+      expect(lock_info).to be_a(Hash)
+      expect(resource_key).to_not be_lockable(lock_manager, ttl)
+      redlock.unlock(lock_info)
+    end
+
     it 'does not load scripts' do
       redis_client.call('SCRIPT', 'FLUSH')