feat: Trello board JSON import (#352)

Closes #27, closes #105

server/api/helpers/boards/process-uploaded-trello-import-file.js

@@ -0,0 +1,38 @@
+const fs = require('fs').promises;
+const rimraf = require('rimraf');
+
+module.exports = {
+  inputs: {
+    file: {
+      type: 'json',
+      required: true,
+    },
+  },
+
+  exits: {
+    invalidFile: {},
+  },
+
+  async fn(inputs) {
+    const content = await fs.readFile(inputs.file.fd);
+    const trelloBoard = JSON.parse(content);
+
+    if (
+      !trelloBoard ||
+      !_.isArray(trelloBoard.lists) ||
+      !_.isArray(trelloBoard.cards) ||
+      !_.isArray(trelloBoard.checklists) ||
+      !_.isArray(trelloBoard.actions)
+    ) {
+      throw 'invalidFile';
+    }
+
+    try {
+      rimraf.sync(inputs.file.fd);
+    } catch (error) {
+      console.warn(error.stack); // eslint-disable-line no-console
+    }
+
+    return trelloBoard;
+  },
+};