[MM-53425]: Added additional checks for POST type APIs (#209)

* [MI-3240]:Fixed security issue [MM-53425] of TODO plugin (#1)

* [MI-3240]:Fixed security issue [MM-53425] of TODO plugin

* [MI-3240]:Fixed review comments

* [MM-53425]:Added body.close methods

* [MI-3276]:Added recovery handler and CheckAuth middleware (#2)

* [MI-3276]:Added recovery handler and CheckAuth middleware

* [MI-3276]:Fixed review comments

* [MI-3423]: Added checks for every post API body (#3)

* [MI-3423]: Added checks for every post API body

* [MI-3423]:Fixed review comments

* [MI-3423]:Fixed review comments

* [MM-53425]:Fixed lint errors

* [MM-53425]:Fixed lint errors

* [MM-53425]:Fixed review comments

go.mod

@@ -3,6 +3,7 @@ module github.com/mattermost/mattermost-plugin-todo
 go 1.13
 
 require (
+	github.com/gorilla/mux v1.8.0
 	github.com/mattermost/mattermost-plugin-api v0.0.11
 	github.com/mattermost/mattermost-server/v5 v5.3.2-0.20200804063212-d4dac31b042a
 	github.com/pkg/errors v0.9.1

go.sum

@@ -219,6 +219,8 @@ github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51
 github.com/gorilla/handlers v1.4.2/go.mod h1:Qkdc/uu4tH4g6mTK6auzZ766c4CA0Ng8+o/OAirnOIQ=
 github.com/gorilla/mux v1.6.2/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/gorilla/mux v1.7.4/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
+github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
+github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/gorilla/schema v1.1.0/go.mod h1:kgLaKoK1FELgZqMAVxx/5cbj0kT+57qxUrAlIO2eleU=
 github.com/gorilla/websocket v1.4.0/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ=
 github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=