Add EF Core and add Postgres as default DB

Tarscord.sln

@@ -3,10 +3,12 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 16
 VisualStudioVersion = 16.0.29102.190
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Tarscord.Core", "src\Tarscord.Core.csproj", "{D44364F2-9C2A-4C32-A083-7E2026557FA0}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Tarscord.Core", "src\Tarscord.Core\Tarscord.Core.csproj", "{D44364F2-9C2A-4C32-A083-7E2026557FA0}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Tarscord.Core.Tests", "tests\Tarscord.Core.Tests.csproj", "{0465984A-3D61-45DC-8316-F818107F1105}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Tarscord.DbMigrator", "src\Tarscord.DbMigrator\Tarscord.DbMigrator.csproj", "{7F849881-B454-405D-9604-C80CB379FE39}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -21,6 +23,10 @@ Global
 		{0465984A-3D61-45DC-8316-F818107F1105}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{0465984A-3D61-45DC-8316-F818107F1105}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{0465984A-3D61-45DC-8316-F818107F1105}.Release|Any CPU.Build.0 = Release|Any CPU
+		{7F849881-B454-405D-9604-C80CB379FE39}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7F849881-B454-405D-9604-C80CB379FE39}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7F849881-B454-405D-9604-C80CB379FE39}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7F849881-B454-405D-9604-C80CB379FE39}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

global.json

@@ -1,7 +1,7 @@
 {
   "sdk": {
-    "version": "6.0.0",
-    "rollForward": "major",
+    "version": "8.0.0",
+    "rollForward": "latestMajor",
     "allowPrerelease": false
   }
 }