add customize command to change background and logo

abra.sh

@@ -1,2 +1,26 @@
 export CUSTOM_CSS_VERSION=v2
 export CUSTOM_FLOWS_VERSION=v1
+
+customize() {
+    if [ -z "$1" ]
+    then
+            echo "Usage: ... customize <assets_path>"
+            exit 1
+    fi
+    # TODO: use env to specify source and target files
+    if [ -e $1/flow_background.jpg ]
+    then
+        echo copy flow_background.jpg
+        abra app cp $APP_NAME $1/flow_background.jpg app:/web/dist/assets/images/
+    fi
+    if [ -e $1/icon_left_brand.svg ]
+    then
+        echo copy icon_left_brand.svg
+        abra app cp $APP_NAME $1/icon_left_brand.svg app:/web/dist/assets/icons/
+    fi
+    if [ -e $1/icon.png ]
+    then
+        echo copy icon.png
+        abra app cp $APP_NAME $1/icon.png app:/web/dist/assets/icons/
+    fi
+}