added frontend and updated backend with docker, wrote some initial instructions

backend/Dockerfile

@@ -0,0 +1,18 @@
+FROM golang:1.20.5-alpine
+
+# Set the Current Working Directory inside the container
+WORKDIR /app
+
+# Copy go mod and sum files
+COPY go.mod go.sum ./
+RUN go mod download
+
+# Copy the source from the current directory to the Working Directory inside the container
+COPY *.go ./
+COPY .. .
+
+# Build the Go app
+RUN CGO_ENABLED=0 GOOS=linux go build -o /htwkalender
+
+# Expose port 8080 to the outside world
+EXPOSE 8080