feat(main): add numberOnly rule

Author: isuke

git-consistent

@@ -132,6 +132,11 @@ const checkValue = (term, value, definition) => {
           if (/\.$/.test(value)) errorMessages.push(`${term} should put dot (.) at the end.`)
         }
         break
+      case 'numberOnly':
+        if (ruleSetting && /^[^0-9].*/.test(value)) {
+          errorMessages.push(`${term} must be number only.`)
+        }
+        break
       case 'ascii':
         if (!ruleSetting && /[\u30a0-\u30ff\u3040-\u309f\u3005-\u3006\u30e0-\u9fcf]/.test(value)) {
           errorMessages.push(`${term} should only alphabet.`)