diff --git a/apps/cr/doc/images/log.svg b/apps/cr/doc/images/log.svg
new file mode 100644
index 0000000..33e2131
--- /dev/null
+++ b/apps/cr/doc/images/log.svg
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+    <!-- Generator: Sketch 3.1.1 (8761) - http://www.bohemiancoding.com/sketch -->
+    <title>log</title>
+    <desc>Created with Sketch.</desc>
+    <defs></defs>
+    <g id="Page-1" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd" sketch:type="MSPage">
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+            <text id="#transaction" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="167" y="33.7716344">#transaction</tspan>
+            </text>
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+                <tspan x="0" y="33.7716344">#client</tspan>
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+                <tspan x="421.5" y="33.7826985">#account</tspan>
+            </text>
+            <text id="#log" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="618" y="34.7826985">#log</tspan>
+            </text>
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+                <tspan x="907" y="563">&lt;- live data</tspan>
+            </text>
+            <text id="&lt;--failover" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="907" y="491">&lt;- failover</tspan>
+            </text>
+            <text id="&lt;--epoch" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="907" y="112">&lt;- epoch</tspan>
+            </text>
+            <text id="&lt;--log-head" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="907" y="639">&lt;- log head</tspan>
+            </text>
+        </g>
+    </g>
+</svg>
\ No newline at end of file
diff --git a/apps/cr/doc/images/merging.svg b/apps/cr/doc/images/merging.svg
new file mode 100644
index 0000000..af6454d
--- /dev/null
+++ b/apps/cr/doc/images/merging.svg
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+<svg width="569px" height="362px" viewBox="0 0 569 362" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:sketch="http://www.bohemiancoding.com/sketch/ns">
+    <!-- Generator: Sketch 3.1.1 (8761) - http://www.bohemiancoding.com/sketch -->
+    <title>merging</title>
+    <desc>Created with Sketch.</desc>
+    <defs></defs>
+    <g id="Page-1" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd" sketch:type="MSPage">
+        <g id="merging" sketch:type="MSLayerGroup" transform="translate(0.000000, -7.000000)">
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+            <text id="Replica-A" sketch:type="MSTextLayer" font-family="Geometria" font-size="24" font-weight="260" fill="#043D3D">
+                <tspan x="106" y="126">Replica A</tspan>
+            </text>
+            <text id="Operations" sketch:type="MSTextLayer" font-family="Geometria" font-size="24" font-weight="260" fill="#043D3D">
+                <tspan x="82" y="31">Operations</tspan>
+            </text>
+            <text id="1" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="270" y="34">1</tspan>
+            </text>
+            <text id="2" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="325" y="34">2</tspan>
+            </text>
+            <text id="3" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="385" y="34">3</tspan>
+            </text>
+            <text id="4" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="442" y="34">4</tspan>
+            </text>
+            <text id="Replica-B" sketch:type="MSTextLayer" font-family="Geometria" font-size="24" font-weight="260" fill="#043D3D">
+                <tspan x="107" y="196">Replica B</tspan>
+            </text>
+            <text id="Replica-C" sketch:type="MSTextLayer" font-family="Geometria" font-size="24" font-weight="260" fill="#043D3D">
+                <tspan x="109" y="271">Replica C</tspan>
+            </text>
+            <path d="M0.5,63.5 L568.5,63.5" id="Line" stroke="#979797" stroke-linecap="square" sketch:type="MSShapeGroup"></path>
+            <text id="GCP" sketch:type="MSTextLayer" font-family="Geometria" font-size="24" font-weight="260" fill="#043D3D">
+                <tspan x="166" y="348">GCP</tspan>
+            </text>
+        </g>
+    </g>
+</svg>
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diff --git a/apps/cr/doc/images/replicas.svg b/apps/cr/doc/images/replicas.svg
new file mode 100644
index 0000000..edff63d
--- /dev/null
+++ b/apps/cr/doc/images/replicas.svg
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+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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+    <!-- Generator: Sketch 3.1.1 (8761) - http://www.bohemiancoding.com/sketch -->
+    <title>replicas</title>
+    <desc>Created with Sketch.</desc>
+    <defs></defs>
+    <g id="Page-1" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd" sketch:type="MSPage">
+        <g id="replicas" sketch:type="MSLayerGroup" transform="translate(-1.000000, 0.000000)">
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+            <text id="write--&gt;" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
+                <tspan x="0" y="34">write -&gt;</tspan>
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+            <text id="&lt;--read" sketch:type="MSTextLayer" font-family="Geometria" font-size="36" font-weight="260" fill="#043D3D">
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diff --git a/apps/cr/doc/images/sup.png b/apps/cr/doc/images/sup.png
new file mode 100644
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Binary files /dev/null and b/apps/cr/doc/images/sup.png differ