Implement addAdbPublicKey endpoint

Reason: manually approve adb connection from web UI does not scale for test automation. Especially those that are using different adb keys on each session (eg: via container)

This changes also added swagger doc endpoint. Using `stf local` command, it will end up at: `http://localhost:7106/docs/`

lib/units/api/controllers/user.js

@@ -3,7 +3,7 @@ var util = require('util')
 var _ = require('lodash')
 var Promise = require('bluebird')
 var uuid = require('uuid')
-
+var adbkit = require('adbkit')
 var dbapi = require('../../../db/api')
 var logger = require('../../../util/logger')
 var datautil = require('../../../util/datautil')
@@ -23,6 +23,7 @@ module.exports = {
 , remoteConnectUserDeviceBySerial: remoteConnectUserDeviceBySerial
 , remoteDisconnectUserDeviceBySerial: remoteDisconnectUserDeviceBySerial
 , getUserAccessTokens: getUserAccessTokens
+, addAdbPublicKey: addAdbPublicKey
 }
 
 function getUser(req, res) {
@@ -400,3 +401,57 @@ function getUserAccessTokens(req, res) {
       })
     })
 }
+
+function addAdbPublicKey(req, res) {
+  var data = req.swagger.params.adb.value
+  adbkit.util.parsePublicKey(data.publickey)
+    .then(function(key) {
+      return dbapi.lookupUsersByAdbKey(key.fingerprint)
+        .then(function(cursor) {
+          return cursor.toArray()
+        })
+        .then(function(users) {
+          return {
+            key: {
+              title: data.title || key.comment,
+              fingerprint: key.fingerprint
+            },
+            users: users
+          }
+        })
+    })
+    .then(function(data) {
+
+      if (data.users.length) {
+        return res.json({
+          success: true
+        })
+      }
+      else {
+        return dbapi.insertUserAdbKey(req.user.email, data.key)
+          .then(function() {
+            return res.json({
+              success: true
+            })
+          })
+      }
+    })
+    .then(function() {
+      req.options.push.send([
+        req.user.group
+      , wireutil.envelope(new wire.AdbKeysUpdatedMessage())
+      ])
+    })
+    .catch(dbapi.DuplicateSecondaryIndexError, function() {
+      // No-op
+      return res.json({
+        success: true
+      })
+    }).catch(function(err) {
+      log.error('Failed to insert new adb key fingerprint: ', err.stack)
+      return res.status(500).json({
+        success: false,
+        message: "Unable to insert new adb key fingerprint to database"
+      })
+    })
+}