Support setting unique columns on console

If one would like to set up a table in postgresql such that two columns together must be unique it would have to do this in sql:

CREATE TABLE someTable (
    id serial primary key,
    col1 int NOT NULL,
    col2 int NOT NULL,
    unique (col1, col2)
)

So, col1 and col2 can repeat, but not at the same time. So, this would be allowed (Not including the id)

1 1
1 2
2 1
2 2

but not this:

1 1
1 2
1 1 -- would reject this insert for violating constraints

Work around

Create table in the sql console, untrack table then track it once created. Caveat : it is not exported in the metadata.json.

[dsandip]

@Sach97 @revskill10 This is being handled in #506. Closing this one.

[revskill10]

I think the need is real and Console UI should support this out of the box, though using SQL is not a big deal. Nice to have feature.