Initial commit carried over from private repo. This is V2.

code/MessengerApi.Configuration/Sources/Environment/EnvironmentConfigurationSource.cs

@@ -0,0 +1,15 @@
+namespace MessengerApi.Configuration.Sources.Environment
+{
+    public class EnvironmentConfigurationSource : IEnvironmentConfigurationSource
+    {
+        public bool HasKey(string key)
+        {
+            return !string.IsNullOrWhiteSpace(System.Environment.GetEnvironmentVariable(key));
+        }
+
+        public T GetValue<T>(string key)
+        {
+            return (T)Convert.ChangeType(System.Environment.GetEnvironmentVariable(key), typeof(T));
+        }
+    }
+}