Changes to address issue #126, #9, and #125.

Concepts structure layout updated.
New term entries added.

concepts/command-service.md

@@ -0,0 +1,13 @@
+---
+title: Command Service
+headline: Command Service
+bodyclass: docs
+layout: docs
+sidenav: doc-side-concepts-nav.html
+type: markdown
+---
+<h2 class="top">Command Service</h2> 
+
+Commands service concept to be added.
+
+

concepts/index.md

@@ -11,9 +11,20 @@ sidenav: doc-side-concepts-nav.html
 <div id="toc" class="toc hide-block"></div>
 This section introduces key concepts of Spine framework and its parts, helps you get a deeper understanding of how it works and provides some usage notes when creating Spine-based cloud application. 
 
-We assume that you are familiar with the basics of Domain-Driven Design. 
+<p class="note">We assume that you are familiar with the basics of Domain-Driven Design.</p> 
 
-Below you can find a typical Spine Event Engine application architecture; its building blocks are also described below.
+Here is a basic view of Spine Event Engine application architecture.
+
+<img src="{{ site.baseurl }}/img/concepts/spine-architecture-diagram-1.0.0.png" alt="Spine Event Engine Architecture">
+
+These are the parts of Spine architecture you are going to interact with when working with Spine. 
+
+<img src="{{ site.baseurl }}/img/concepts/spine-architecture-diagram-1.0.0-faded.png" alt="Spine Event Engine Architecture">
+
+
+
+
+
 
 
 

concepts/integration-event.md

@@ -0,0 +1,11 @@
+---
+title: Integration Event
+headline: Integration Event
+bodyclass: docs
+layout: docs
+sidenav: doc-side-concepts-nav.html
+type: markdown
+---
+<h2 class="top">Integration Event</h2> 
+
+Integration Event concept to be added.

concepts/process-manager.md

@@ -10,7 +10,7 @@ type: markdown
 
 Process Manager is an independent component that reacts to domain events in a cross-aggregate eventually consistent manner. It serves as a centralized processing unit that maintains the state sequence and defines the next processing step based on intermediate results. 
 
-[Process manager](/java/process-manager.md) can be both Command Handler and Event Handler.
+Process Manager can be both Command Handler and Event Subscriber.
 
 <p class="note">We recommend to use process ID when integrating with side services. 
 </p>

concepts/rejection.md

@@ -8,9 +8,11 @@ type: markdown
 ---
 <h2 class="top">Rejection</h2> 
 
-Rejection is a state of business logic which can be handled by the end user. 
-In Spine, rejections are defined as Protocol buffer messages. Consider the following examples of rejections: 
+Rejection is a state of business logic which can be handled by the end user. It's a special “negative” kind of events. 
+
+In Spine, rejections are defined as Protobuf messages. If an event is a fact of something that happened to a domain model, a rejection is a fact that states the reason why a command was not handled. 
+
+Consider the following examples of rejections: 
 * `CreditCardValidationDecllined`, 
 * `OrderCannotBeEmpty`, 
-* `InsufficientFunds`.
-
+* `InsufficientFunds`.

index.html

@@ -11,11 +11,10 @@
             <div class="col-md-7">
                 <h2>Welcome to the Spine developer documentation</h2>
                 <p>
-                    Here you can learn about key concepts, find quick starts, reference
+                    Here you can learn about <a href="concepts">key concepts</a>, find quick starts, reference
                     material, tutorials, and more.
-                    If you’re new to the framework we recommend that you read the <a href="guides/">Introduction</a>
-                    guide to find out more about the framework and how it works.
-                    Or, if you want to see Spine in action first, visit the <a href="quickstart/">QuickStart</a>.</p>
+                    If you’re new to the framework we recommend that you read the <a href="guides/">Introduction guide</a> to find out more about the framework and how it works.
+                    Or, if you want to see Spine in action first, visit the <a href="quickstart/">Quick Start</a>.</p>
             </div>
         </div>
     </div>