[$50] Add new field "title" to the "Job" model

[maxceem]

We need to add a new field to the "Job" model to keep the job title:

• type: string, required, max length 64
• update swagger/postman
• create a migration script
  • for existent records populate it with the value from description
• update all related endpoints to support it
• update ES processor / es-mapping if needed

[maxceem]

Contest https://www.topcoder.com/challenges/30161319 has been created for this ticket.

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[maxceem]

@imcaizheng this is open for pick up now.

[maxceem]

Contest https://www.topcoder.com/challenges/30161319 has been updated - it has been assigned to aaron2017.

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[imcaizheng]

PR created #95

[imcaizheng]

PR for taas-es-processor topcoder-platform/taas-es-processor#7

[maxceem]

@nkumar-topcoder also, during migration we have to update the mapping in ES similar to #22 (comment):

PUT /job/_mapping
{
  "properties": {
    "title": {
       "type": "text"
    }
  }
}

[maxceem]

Added a couple of small fixes 205f264. Otherwise all works good.