feat(auth): implement user authentication system

backend/node_modules/v8-to-istanbul/lib/branch.js

@@ -0,0 +1,28 @@
+module.exports = class CovBranch {
+  constructor (startLine, startCol, endLine, endCol, count) {
+    this.startLine = startLine
+    this.startCol = startCol
+    this.endLine = endLine
+    this.endCol = endCol
+    this.count = count
+  }
+
+  toIstanbul () {
+    const location = {
+      start: {
+        line: this.startLine,
+        column: this.startCol
+      },
+      end: {
+        line: this.endLine,
+        column: this.endCol
+      }
+    }
+    return {
+      type: 'branch',
+      line: this.startLine,
+      loc: location,
+      locations: [Object.assign({}, location)]
+    }
+  }
+}