add random enum with weight feature

Author: LinuxSuRen

docs/site/content/zh/latest/tasks/mock/simple.yaml

@@ -12,12 +12,12 @@ items:
         {
           "count": 1,
           "items": [{
-            "title": "fix: there is a bug on page {{ randEnum "one" }}",
+            "title": "fix: there is a bug on page {{ randEnum "one" "two" "three" "four" }}",
             "number": {{randInt 100 199}},
             "float": {{randFloat 0.0 1.0}},
+            "status": "{{randWeightEnum (weightObject 4 "open") (weightObject 1 "closed")}}",
             "message": "{{.Response.Header.server}}",
-            "author": "someone",
-            "status": "success",
+            "author": "{{env "USER"}}",
             "created": "{{ now.Format "2006-01-02T15:04:05Z07:00" }}"
           }],
           "uptime": "{{uptime}}"

docs/site/content/zh/latest/tasks/template.md

@@ -10,4 +10,28 @@ title = "用例模板"
 
 ```
 182{{shuffle "09876543"}}
-```
+```
+
+## 带权重的随机枚举
+
+下面的代码以 80% 的概率返回 `open`，以 20% 的概率返回 `closed`：
+
+```
+{{randWeightEnum (weightObject 4 "open") (weightObject 1 "closed")}}
+```
+
+## 时间
+
+下面的代码可以生成当前时间，并制定时间格式：
+
+```
+{{ now.Format "2006-01-02T15:04:05Z07:00" }}
+```
+
+## 环境变量
+
+下面的代码可以获取环境变量 `SHELL` 的值，在需要使用一个全局变量的时候，可以使用这个模板函数：
+
+```
+{{ env "SHELL" }}
+```