add update instructions for 1.6.0

UPDATE.md

@@ -1,4 +1,28 @@
-## 1.4.x -> 1.5.0
+## 1.5.x -> 1.6.0
+
+pull the update: `git pull`  
+make these changes in your config.json file:
+```diff
+...
+	"style": {
+		...
++		"homepageLayout": "catask"
+	},
+...
+```
+
+after that, log into your mariadb/mysql console and execute these commands:
+```
+USE <catask database name>;
+```
+```
+ALTER TABLE questions ADD COLUMN cw VARCHAR(255) NOT NULL DEFAULT '';
+```
+```
+ALTER TABLE answers ADD COLUMN cw VARCHAR(255) NOT NULL DEFAULT '';
+```
+
+## 1.4.x -> 1.5.x
 
 pull the update as usual: `git pull`  
 run `pip install -r requirements.txt` again to install newly required packages  
@@ -8,7 +32,7 @@ make the following changes in your config.json file:
     "instance": {
         ...
 -        "image": "/static/img/ca_screenshot.png",
-+        "image": "/static/icons/favicon/android-chrome-192x192.png",
++        "image": "/static/icons/favicon/android-chrome-512x512.png",
         ...
     },
 +    "style": {
@@ -20,7 +44,7 @@ make the following changes in your config.json file:
 +        "tintColors": false,
 +        "infoBoxLayout": "column"
 +    },
-+    "trimContentAfter": "50",
++	 "trimContentAfter": "50",
 ...
 ```