feat: Improved onboarding documents (#970)

* feat: New onboarding documents

* Images -> blocks

* Add tips

* test: removes assumptions of welcome documents

this actually results in the tests being much more understandable too

* add db flag when document was created from welcome flow

server/migrations/20190704070630-welcome-docs.js

@@ -0,0 +1,12 @@
+module.exports = {
+  up: async (queryInterface, Sequelize) => {
+    await queryInterface.addColumn('documents', 'isWelcome', {
+      type: Sequelize.BOOLEAN,
+      allowNull: false,
+      defaultValue: false
+    });
+  },
+  down: async (queryInterface, Sequelize) => {
+    await queryInterface.removeColumn('documents', 'isWelcome');
+  }
+}