array_type_field_filter: Adds contains filter

1. Adds new filter for array type field.
2. From this filter you can search from array type field.

Signed-off-by: shubhisood <shubhi.sood@sourcefuse.com>

lib/model-utils.js

@@ -88,6 +88,7 @@ const operators = {
   ilike: 'ILIKE',
   nilike: 'NOT ILIKE',
   regexp: 'REGEXP',
+  contains: '@>',
 };
 
 /*
@@ -449,6 +450,7 @@ ModelUtils._coerce = function(where, options, modelDef) {
             case 'inq':
             case 'nin':
             case 'between':
+            case 'contains':
               try {
                 val = coerceArray(val);
               } catch (e) {