diff --git a/lib/models/acl.js b/lib/models/acl.js
index 6b3f6d46..db341f62 100644
--- a/lib/models/acl.js
+++ b/lib/models/acl.js
@@ -40,4 +40,6 @@ var ACLSchema = {
     status: String, // Enabled/disabled
     created: Date,
     lastUpdated: Date
-}
\ No newline at end of file
+}
+
+// readAccess, writeAccess --> public, userId, role
\ No newline at end of file
diff --git a/lib/models/application.js b/lib/models/application.js
index 173d2b97..b19b445b 100644
--- a/lib/models/application.js
+++ b/lib/models/application.js
@@ -1,17 +1,26 @@
-// Application model
+/**
+ * Data model for Application
+ */
 var ApplicationSchema = {
 
     // Basic information
     id: {type: String, required: true},
     name: {type: String, required: true},
     description: String, // description
-    icon: String, // The icon url
-    public: Boolean,
+    icon: String, // The icon image url
+
+    public: Boolean, // Do we list the application in the public catalog?
     permissions: [String],
 
-    userId: String,
+    owner: String, // The user id of the developer who registers the application
+    collaborators: [String], // A list of users ids who have permissions to work on this app
 
-    status: String,
+    // EMail
+    email: String, // e-mail address
+    emailVerified: Boolean, // Is the e-mail verified
+
+
+    status: String, // Status of the application, enabled/disabled
 
     // Keys
     clientKey: String,
@@ -24,18 +33,24 @@ var ApplicationSchema = {
     pushPlatforms: [String],
     pushCredentials: [],
 
-    // Authentication
+    // User Authentication
     authenticationEnabled: Boolean,
     anonymousAllowed: Boolean,
     schemes: [String], // Basic, facebook, github, google
     attachedCredentials: [],
 
-   // email
-    email: String, // e-mail address
-    emailVerified: Boolean, // Is the e-mail verified
-
-    collaborators: [String], // A list of users ids who have permissions to work on this app
 
     created: Date,
     lastUpdated: Date
 };
+
+
+/**
+ * Application management functions
+ */
+
+// Register a new application
+
+
+
+
diff --git a/lib/models/installation.js b/lib/models/installation.js
index 03d1b0ed..a734dc64 100644
--- a/lib/models/installation.js
+++ b/lib/models/installation.js
@@ -1,4 +1,17 @@
 // See Device registration
 var InstallationSchema = {
-
+    id: {
+        type: String,
+        required: true,
+        id: 1
+    },
+    appId: String,
+    appVersion: String,
+    userId: String,
+    deviceToken: String,
+    deviceType: String,
+    subscriptions: [String],
+    created: Date,
+    lastModified: Date,
+    status: String
 };
diff --git a/lib/models/role.js b/lib/models/role.js
index 0bd17dae..74421708 100644
--- a/lib/models/role.js
+++ b/lib/models/role.js
@@ -1,10 +1,10 @@
 // Role model
 var RoleSchema = {
     id: {type: String, required: true},
-    name: {type: String, required: true},
+    name: {type: String, required: true}, // The name of a role
+    description: String,
     roles: [String], // A role can be an aggregate of other roles
     users: [String], // A role contains a list of users
-
     created: Date,
     lastUpdated: Date
 }
\ No newline at end of file
diff --git a/lib/models/user.js b/lib/models/user.js
index 545e772c..0f170093 100644
--- a/lib/models/user.js
+++ b/lib/models/user.js
@@ -1,3 +1,24 @@
+/**
+ * User Model
+ Active User
+ Explicit vs. Implicit
+ Signup
+ Removing the User from the System
+ Login
+ Logout
+ User Management
+ Email Verification
+ Password Reset
+ Forgot Username
+ Using Social Identities
+ Facebook
+ Google+
+ LinkedIn
+ Twitter
+ User Discovery
+ Username Existence Check
+ * @type {{question: *, answer: *}}
+ */
 var ChallengeSchema = {
     // id: String,
     question: String,