Evalai: Add feature to invite users to host team using URL

[deshraj]

Very similar to #1346.

Deliverables

Add a feature to invite new team member to a host team using a unique URL. Also, don't forget to write unit tests. :)

Steps

1. user1 enters the email of his teammate (let's say user2)
2. Send an email to user2 (if he/she is registered on EvalAI) with a unique URL
3. user2 clicks on the URL to accept the invitation to the team.
4. user1 gets an email saying that "user2 has accepted your invite to team " (we can iterate over the email message later)

Some important points to note

• [ ] Checks performed before inviting to the team should be similar to current invitation logic

[Ram81]

@deshraj can I take this one ?

[sudhanshuchopra]

@deshraj @Ram81 @RishabhJain2018 If currently no one is working on it.
Can I work on it ?

[guyandtheworld]

@aka-jain @RishabhJain2018 @deshraj I completed the other similar issue, can I work on this?

[deshraj]

@sudhanshuchopra please let us know if you can work on this? If we don't hear back from @sudhanshuchopra, then @isht3 you can work on it. :)

[sudhanshuchopra]

Yes @deshraj you can assign it to @isht3

[guyandtheworld]

Only tests for this are pending, I'll do the PR tomorrow.

[deshraj]

@isht3: any update?

[guyandtheworld]

@deshraj Done!

[RishabhJain2018]

This issue is still open to work :).

[yashdusing]

@deshraj @RishabhJain2018 What's the difference between this and #1346 ?

[gautamjajoo]

@yashdusing This issue is for inviting members for host team. And the other one is for inviting members to join participant team.

[yashdusing]

@RishabhJain2018 @deshraj @gautamjajoo I'd like to take this up. I haven't been assigned any issues yet and have finished all my previous work

[yashdusing]

@Ram81 @RishabhJain2018 Can I work on this issue?

[RishabhJain2018]

Sure, you can work on this issue.

[devanshbatra04]

Taking this up!