add pre_deploy.sh script for dotter

.dotter/handlebars_helpers/flatten_table.rhai

@@ -0,0 +1,30 @@
+/*
+* Flatten a table into a list of values.
+* The table has to be in the form of
+* ```toml
+* [table.subtable]
+* variable1 = ["value1", "value2"]
+*
+* [table.subtable]
+* variable2 = ["value3", "value4"]
+*
+* then we use it in handlerbars like this:
+*
+* {{ flatten_table table.subtable }}
+*
+* and it will return an array with all the arrays of subtable
+*/
+
+if type_of(params[0]) != "map" {
+  return;
+}
+
+let table = params[0];
+
+let result = [];
+
+for value in table.values() {
+  result.append(value);
+}
+
+result