Add documentation for the laundrify integration (#21360)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

.vscode/cSpell.json

@@ -48,6 +48,7 @@
     "icloud",
     "IFTTT",
     "kardon",
+    "laundrify",
     "Lutron",
     "macos",
     "Meteobridge",

source/_integrations/laundrify.markdown

@@ -0,0 +1,49 @@
+---
+title: "laundrify"
+description: "Instructions on how to integrate laundrify within Home Assistant."
+ha_category:
+  - Binary Sensor
+ha_release: 2022.6
+ha_iot_class: Cloud Polling
+ha_domain: laundrify
+ha_platforms:
+  - binary_sensor
+ha_codeowners:
+  - '@xLarry'
+ha_config_flow: true
+---
+
+Monitor the status of your washing machine or dryer within Home Assistant using a [laundrify](https://laundrify.de/) WiFi power plug.
+
+The following device types are currently supported by the integration:
+
+- Binary Sensor
+
+## Generate an Auth Code
+
+*Please note that the laundrify App v1.12.0 is required to activate the Home Assistant integration.*
+
+The integration requires an Auth Code to complete the account linking. Open the laundrify App and tap on `Home Assistant -> Integration aktivieren` to generate your code.
+
+<p class='img'>
+  <img src='/images/integrations/laundrify/generate-code.png' alt='Screenshot: generate an Auth Code in the laundrify App'>
+</p>
+
+Your code will expire within 60 minutes after activation. Make sure to configure your integration in time.
+
+{% include integrations/config_flow.md %}
+
+{% configuration_basic %}
+code:
+  description: "Auth Code that can be obtained in the laundrify App (see above), e.g., `123-456`."
+  required: true
+  type: string
+{% endconfiguration_basic %}
+
+{% include integrations/option_flow.md %}
+{% configuration_basic %}
+poll_interval:
+  description: Interval for polling the laundrify backend (in seconds)
+  default: 60
+  type: integer
+{% endconfiguration_basic %}