Added global psalm config

psalm.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0"?>
+<psalm xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="https://getpsalm.org/schema/config"
+       name="Psalm for Poakium"
+       useDocblockTypes="true"
+       errorLevel="7"
+       strictBinaryOperands="false"
+       rememberPropertyAssignmentsAfterCall="true"
+       checkForThrowsDocblock="false"
+       throwExceptionOnError="0"
+       ensureArrayStringOffsetsExist="true"
+       ensureArrayIntOffsetsExist="false"
+       resolveFromConfigFile="true"
+       xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="packages"/>
+        <directory name="tools"/>
+        <ignoreFiles>
+            <directory name="vendor"/>
+        </ignoreFiles>
+    </projectFiles>
+
+    <issueHandlers>
+        <UndefinedClass>
+            <errorLevel type="suppress">
+                <referencedClass name="ReflectionAttribute"/>
+            </errorLevel>
+        </UndefinedClass>
+    </issueHandlers>
+</psalm>

tools/psalm/composer.json

@@ -0,0 +1,5 @@
+{
+    "require-dev": {
+        "vimeo/psalm": "^4.27"
+    }
+}