Implement a console-based social networking application (similar to Twitter) satisfying the scenarios below.
Posting: Alice can publish messages to a personal timeline
> Alice -> I love the weather today
> Bob -> Damn! We lost!
> Bob -> Good game though.
Reading: Bob can view Alice’s timeline
> Alice
> I love the weather today (5 minutes ago)
> Bob
> Good game though. (1 minute ago)
> Damn! We lost! (2 minutes ago)
Following: Charlie can subscribe to Alice’s and Bob’s timelines, and view an aggregated list of all subscriptions
> Charlie -> I'm in New York today! Anyone wants to have a coffee?
> Charlie follows Alice
> Charlie wall
> Charlie - I'm in New York today! Anyone wants to have a coffee? (2 seconds ago)
> Alice - I love the weather today (5 minutes ago)
> Charlie follows Bob
> Charlie wall
> Charlie - I'm in New York today! Anyone wants to have a coffee? (15 seconds ago)
> Bob - Good game though. (1 minute ago)
> Bob - Damn! We lost! (2 minutes ago)
> Alice - I love the weather today (5 minutes ago)