Extend backend to support new suspend feature

graph/typeDefs.graphql

@@ -669,6 +669,23 @@ input CreateDontAgreeInput {
   message: String
 }
 
+# Input for suspendUser mutation.
+input SuspendUserInput {
+
+  # id of target user.
+  id: ID!
+
+  # message to be sent to the user.
+  # TODO: should this be required?
+  message: String
+
+  # If set, the user is requested to change its username.
+  mustChangeUsername: Boolean
+
+  # If set, the suspension lasts at least until specified date.
+  until: Date
+}
+
 # DeleteActionResponse is the response returned with possibly some errors
 # relating to the delete action attempt.
 type DeleteActionResponse implements Response {
@@ -741,7 +758,7 @@ type EditCommentResponse implements Response {
   comment: Comment
 
   # An array of errors relating to the mutation that occured.
-  errors: [UserError]  
+  errors: [UserError]
 }
 
 # All mutations for the application are defined on this object.
@@ -765,8 +782,8 @@ type RootMutation {
   # Sets User status. Requires the `ADMIN` role.
   setUserStatus(id: ID!, status: USER_STATUS!): SetUserStatusResponse
 
-  # Sets User status to BANNED and canEditName to true. It sends a message to the banned User. Requires the `ADMIN` role.
-  suspendUser(id: ID!, message: String): SuspendUserResponse
+  # Suspends a user. Requires the `ADMIN` role.
+  suspendUser(input: SuspendUserInput!): SuspendUserResponse
 
   # Sets Comment status. Requires the `ADMIN` role.
   setCommentStatus(id: ID!, status: COMMENT_STATUS!): SetCommentStatusResponse