Load configs from file to config db

Partially addresses HospitalRun/hospitalrun-frontend#153
and HospitalRun/hospitalrun-frontend/#631

.eslintrc

@@ -2,6 +2,9 @@
   "env": {
     "node": true
   },
+  "parserOptions": {
+    "ecmaVersion": 6
+  },
   "rules": {
     "array-bracket-spacing": [2, "never"],
     "block-scoped-var": 2,

routes/10-couchproxy.js

@@ -1,5 +1,58 @@
 var forward = require('../forward.js');
 
+var CONFIGS_TO_LOAD = {
+  'config_disable_offline_sync': 'disableOfflineSync',
+  'config_use_google_auth': 'useGoogleAuth',
+  'config_log_metrics': 'logNetworkMetrics',
+  'config_external_search': 'searchURL'
+};
+
 module.exports = function(app, config) {
+  var nano = require('nano')(config.couchAuthDbURL);
+  var configDB = nano.use('config');
+  function loadConfigs() {
+    var configIds = Object.keys(CONFIGS_TO_LOAD);
+    configDB.fetch({keys: configIds}, (err, configValues) => {
+      if (err) {
+        console.log('Error getting configurations to update', err);
+      } else {
+        let configsToUpdate = [];
+        configValues.rows.forEach((configValue) => {
+          var matchingConfig = CONFIGS_TO_LOAD[configValue.key];
+          var valueFromConfigFile = config[matchingConfig];
+           if (!valueFromConfigFile) {
+             valueFromConfigFile = false;
+           }
+          if (configValue.key === 'config_external_search' &&
+              valueFromConfigFile && valueFromConfigFile !== '') {
+            valueFromConfigFile = true;
+          }
+          var dbConfigValue = '';
+          if (!configValue.error && configValue.doc) {
+            dbConfigValue = configValue.doc.value;
+          }
+          if (dbConfigValue !== valueFromConfigFile) {
+            let docToUpdate = configValue.doc;
+            if (!docToUpdate) {
+              docToUpdate = {
+                _id: configValue.key
+              };
+            }
+            docToUpdate.value = valueFromConfigFile;
+            configsToUpdate.push(docToUpdate);
+          }
+        });
+        if (configsToUpdate.length > 0) {
+          configDB.bulk({docs: configsToUpdate}, (err) => {
+            if (err) {
+              console.log('Error updating configs:', err);
+            }
+          });
+        }
+      }
+    });
+
+  }
+  loadConfigs();
   app.use('/db/', forward(config.couchDbURL, config, true));
 };