fix: Add start script for apps

Author: raymondfeng

packages/cli/generators/project/templates/package.json

@@ -40,6 +40,9 @@
     <% if (project.prettier || project.tslint) { -%>
     "posttest": "npm run lint",
     <% } -%>
+    <% if (project.projectType === 'application') { -%>
+    "start": "npm run build && node .",
+    <% } -%>
     "prepare": "npm run build"
   },
   "repository": {

packages/cli/generators/project/templates/package.plain.json

@@ -40,6 +40,9 @@
     <% if (project.prettier || project.tslint) { -%>
     "posttest": "npm run lint",
     <% } -%>
+    <% if (project.projectType === 'application') { -%>
+    "start": "npm run build && node .",
+    <% } -%>
     "prepare": "npm run build"
   },
   "repository": {

packages/cli/test/project.js

@@ -56,11 +56,19 @@ module.exports = function(projGenerator, props, projectType) {
           assert.fileContent('package.json', '"@loopback/core"');
           assert.fileContent('package.json', '"@loopback/context"');
           assert.fileContent('package.json', '"@loopback/rest"');
+          assert.jsonFileContent('package.json', {
+            scripts: {
+              start: 'npm run build && node .',
+            },
+          });
         }
         if (projectType === 'extension') {
           assert.fileContent('package.json', '"@loopback/core"');
           assert.fileContent('package.json', '"@loopback/context"');
           assert.noFileContent('package.json', '"@loopback/rest"');
+          assert.noJsonFileContent('package.json', {
+            start: 'npm run build && node .',
+          });
         }
       });
     });