diff --git a/migrations/20140831_increase_gems_for_previous_contributions.js b/migrations/20140831_increase_gems_for_previous_contributions.js
new file mode 100644
index 0000000000..b8e30691ae
--- /dev/null
+++ b/migrations/20140831_increase_gems_for_previous_contributions.js
@@ -0,0 +1,79 @@
+// IMPORTANT:
+//
+// run like this to capture all output:
+// node 20140831_increase_gems_for_previous_contributions.js  > 20140831_increase_gems_for_previous_contributions_output.txt
+
+
+var migrationName = '20140831_increase_gems_for_previous_contributions';
+// author: Alys (d904bd62-da08-416b-a816-ba797c9ee265)
+
+/**
+ * https://github.com/HabitRPG/habitrpg/issues/3933
+ * Increase Number of Gems for Contributors
+ * 
+ * Increase everyone's gems per their contribution level.
+ * Originally they were given 2 gems per tier.
+ * Now they are given 3 gems per tier for tiers 1,2,3
+ *                and 4 gems per tier for tiers 4,5,6,7
+ * So that means an EXTRA 1 for tier 1,
+ *                        2 for tier 2,
+ *                        3 for tier 3,
+ *                        5 for tier 4,
+ *                        7 for tier 5,
+ *                        9 for tier 6,
+ *                       11 for tier 7,
+ *                       11 for tier 8 (moderators = tier 7 + admin privileges),
+ *                     none for tier 9 (staff)
+ */
+
+var mongo = require('mongoskin');
+var _ = require('lodash');
+
+
+///////////////////    UNCOMMENT *ONE* OF THESE LINES:    ///////////////////
+// var dbUsers = mongo.db('lefnire:mAdn3s5s@charlotte.mongohq.com:10015/habitrpg_large?auto_reconnect').collection('users');   // @lefnire production?
+// var dbUsers = mongo.db('localhost:27017/habitrpg_old?auto_reconnect').collection('users');   // @lefnire habitrpg_old
+// var dbUsers = mongo.db('localhost:27017/habitrpg?auto_reconnect').collection('users');   // for local testing by script author (e.g., vagrant install)
+
+
+var fields = {'migration':1,
+    'contributor.level':1,
+    'auth.local.username':1,
+    'balance':1,
+    };
+
+dbUsers.findEach({ $and: [
+  { 'contributor.level': {$gt:0} },
+  { 'contributor.level': {$lt:9} }
+]}, fields, {batchSize:250}, function(err, user){
+    if (!user) err = '!user';
+    if (err) {return console.error(err);}
+
+    var set = {'migration': migrationName};
+
+    var tier = user.contributor.level;
+    var extraGems = tier; // tiers 1,2,3
+    if (tier > 3) {
+        extraGems = 3 + (tier - 3) * 2;
+    }
+    if (tier == 8) {
+        extraGems = 11; // mods (tier 8) are tier 7 in terms of gems awarded
+    }
+    extraBalance = extraGems / 4;
+    set['balance'] = user.balance + extraBalance;
+
+    // Display current state of user:
+    console.log("\n" + user._id + "  " + user.auth.local.username + ":\n" +
+        "  contrib tier          :  " + tier + "\n" +
+        "  balance before        :  " + user.balance + "\n" +
+        "  balance (gems) added  :  " + extraBalance + " (" +
+                                        extraGems + ")" + "\n" +
+        "  expected balance after:  " + (user.balance + extraBalance));
+
+    //console.log(JSON.stringify(user, null, "  "));
+    //console.log("set: "   + JSON.stringify(set,   null, "  "));
+
+    dbUsers.update({_id:user._id}, {$set:set, $inc:{_v:1}});
+
+    // No progress counter because we print output for every user.
+});
diff --git a/migrations/20140831_increase_gems_for_previous_contributions_FINAL_CHECK.js b/migrations/20140831_increase_gems_for_previous_contributions_FINAL_CHECK.js
new file mode 100644
index 0000000000..d11e1b29fc
--- /dev/null
+++ b/migrations/20140831_increase_gems_for_previous_contributions_FINAL_CHECK.js
@@ -0,0 +1,43 @@
+// IMPORTANT:
+//
+// run like this to capture all output:
+// node 20140831_increase_gems_for_previous_contributions_FINAL_CHECK.js  > 20140831_increase_gems_for_previous_contributions_FINAL_CHECK_output.txt
+
+
+
+// 20140831_increase_gems_for_previous_contributions_FINAL_CHECK.js
+// author: Alys (d904bd62-da08-416b-a816-ba797c9ee265)
+
+/**
+ * Run this script immediately after
+ *   20140831_increase_gems_for_previous_contributions.js
+ * to capture the actual gem balance in case we need it later for
+ * handling complaints that the right number of gems weren't added.
+ */
+
+var mongo = require('mongoskin');
+var _ = require('lodash');
+
+///////////////////    UNCOMMENT *ONE* OF THESE LINES:    ///////////////////
+// var dbUsers = mongo.db('lefnire:mAdn3s5s@charlotte.mongohq.com:10015/habitrpg_large?auto_reconnect').collection('users');   // @lefnire production?
+// var dbUsers = mongo.db('localhost:27017/habitrpg_old?auto_reconnect').collection('users');   // @lefnire habitrpg_old
+var dbUsers = mongo.db('localhost:27017/habitrpg?auto_reconnect').collection('users');   // for local testing by script author (e.g., vagrant install)
+
+
+var fields = {
+    'auth.local.username':1,
+    'balance':1,
+    };
+
+dbUsers.findEach({ $and: [
+  { 'contributor.level': {$gt:0} },
+  { 'contributor.level': {$lt:9} }
+]}, fields, {batchSize:250}, function(err, user){
+    if (!user) err = '!user';
+    if (err) {return console.error(err);}
+
+    console.log("\n" + user._id + "  " + user.auth.local.username + ":\n" +
+        "  actual balance after  :  " + user.balance);
+
+    // No progress counter because we print output for every user.
+});