migrate to v4

public/v4/apps/mongodb.yml

@@ -0,0 +1,40 @@
+captainVersion: 4
+services:
+  $$cap_appname:
+    image: mongo:$$cap_mongo_version
+    volumes:
+      - $$cap_appname-db-data:/data/db
+      - $$cap_appname-db-config:/data/configdb
+    restart: always
+    environment:
+      MONGO_INITDB_ROOT_USERNAME: $$cap_mongo_username
+      MONGO_INITDB_ROOT_PASSWORD: $$cap_mongo_password
+    caproverExtra:
+      notExposeAsWebApp: "true"
+caproverOneClickApp:
+  variables:
+    - id: $$cap_mongo_version
+      label: MongoDB Version
+      defaultValue: "4"
+      description: Check out their Docker page for the valid tags https://hub.docker.com/r/library/mongo/tags/
+      validRegex: /^([^\s^\/])+$/
+    - id: $$cap_mongo_username
+      label: MongoDB RootUsername
+      defaultValue: root
+      description: Only use alphanumeric chars.
+      validRegex: /^([a-zA-Z0-9])+$/
+    - id: $$cap_mongo_password
+      label: MongoDB password
+      validRegex: /^\s*\S.*$/
+  instructions:
+    start: >-
+      MongoDB is a cross-platform document-oriented database. Classified as a NoSQL database program, MongoDB uses JSON-like documents with schemas. 
+
+       After installation on CapRover, it will be available as srv-captain--YOUR_CONTAINER_NAME at port 27017 to other CapRover apps.
+
+       Enter your MongoDB Configuration parameters and click on next. It will take about a minute for the process to finish.
+    end: "MongoDB is deployed and available as srv-captain--$$cap_appname:27017 to other apps. For example with NodeJS: mongoose.connect('mongodb://srv-captain--$$cap_appname/mydatabase?authSource=admin', {userMongoClient: true});"
+  displayName: MongoDB
+  isOfficial: true
+  description: MongoDB is a cross-platform document-oriented database program. Classified as a NoSQL database program
+  documentation: Taken from https://hub.docker.com/r/mongo/