Add MPOD link in providers list

src/links/v1/providers.json

@@ -140,6 +140,17 @@
         "link_type": "external"
       }
     },
+    {
+      "type": "links",
+      "id": "mpod",
+      "attributes": {
+        "name": "Material Properties Open Database (MPOD)",
+        "description": "The Material Properties Open Database (MPOD) is a web-based, open access repository of quantitative information about the physical properties of crystalline materials. MPOD is oriented to design engineers, scientists, science teachers and students. Properties are generally treated as tensor magnitudes. In MPOD the compact matrix notation is applied. To bring an intuitive view of tensor properties, so-called longitudinal properties surfaces are displayed. 3D printing of properties surfaces is implemented via creation of stl files. A dictionary of properties definitions is included. Eventually, comments are added. Syntax and notation in MPOD files is oriented towards matching IUCr standards and so tries to comply with CIF format.",
+        "base_url": "https://providers.optimade.org/index-metadbs/mpod",
+        "homepage": "http://mpod.cimav.edu.mx",
+        "link_type": "external"
+      }
+    },
     {
       "type": "links",
       "id": "necro",