Failed to run successfully

[escrowdis]

Hi Connor,
Thank you so much for this demo. It looks very useful for a newbie like me, but I failed to run it on my machine and need some advice to fix it. Here's what I did.

1. git clone
2. npm install
3. source .env.example (no idea if this is necessary)
4. node src/utils/seed.js

Stuck on step 3 which showed the error messages as follows:

****/task-app-backend/node_modules/mailgun-js/lib/mailgun.js:16
      throw new Error('apiKey value must be defined!')
      ^

Error: apiKey value must be defined!
    at new Mailgun (****/website/task-app-backend/node_modules/mailgun-js/lib/mailgun.js:16:13)
    at create (****/website/task-app-backend/node_modules/mailgun-js/lib/mailgun.js:239:10)
    at Object.<anonymous> (****/website/task-app-backend/src/utils/emails.js:5:38)
    at Module._compile (internal/modules/cjs/loader.js:701:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
    at Module.load (internal/modules/cjs/loader.js:600:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
    at Function.Module._load (internal/modules/cjs/loader.js:531:3)
    at Module.require (internal/modules/cjs/loader.js:637:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at Object.<anonymous> (****/website/task-app-backend/src/utils/index.js:4:22)
    at Module._compile (internal/modules/cjs/loader.js:701:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
    at Module.load (internal/modules/cjs/loader.js:600:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
    at Function.Module._load (internal/modules/cjs/loader.js:531:3)
    at Module.require (internal/modules/cjs/loader.js:637:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at Object.<anonymous> (****/website/task-app-backend/src/models/user.js:2:26)
    at Module._compile (internal/modules/cjs/loader.js:701:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
    at Module.load (internal/modules/cjs/loader.js:600:32)

Thanks!