Update rebuild.sh to not be position dependent

paper-houses-theme/rebuild.sh

@@ -2,10 +2,15 @@
 
 # Should be run as ./rebuild.sh
 
-if ! command -v sass &> /dev/null
-then
-    echo "sass could not be found. Please install sass"
-    exit
-fi
+(
+    # CD to the directory that this file is in
+    cd $(dirname "$0")
 
-sass -w assets/styles/main.scss assets/built/main.css
+    if ! command -v sass &> /dev/null
+    then
+        echo "sass could not be found. Please install sass"
+        exit
+    fi
+
+    sass -w assets/styles/main.scss assets/built/main.css
+)