When a posting has an offer proposal that has been accepted, it should be excluded from search results

[brozeph]

Today, status of a posting transaction is stored in the transactions collection and there are three possible values:

• pending
• completed
• expired

When the transaction status is set to pending or completed, the posting for which the transaction applies should no longer show up in search results (i.e. should be removed from the ES index).

[brozeph]

All set on this - assigning to @that1guy for additional comments and verification

[that1guy]

Issue described in #90